PSA: Guys the supply of these replacement Air Core Motors seems to have dried up and they are much harder to find now. Several links here and in the video description text to help you though. Try all of the links on both eBay and Amazon to find the best price for the calibration(s) you need. They were available for a time as outfits like Dorman that were remanufacturing these dash clusters, as well as local speedometer repair shops, provided enough demand to warrant producing them still. But as of March 12, 2020 they are basically in the new old stock (NOS) stage now and every one of them will be an easter egg hunt. The "F" calibration is the hardest to obtain now, I see only two sellers on eBay affiliate linked below: One seller on eBay, USDashWorks, who is selling the actual units I have bought in the past, has them back in stock. They have a core charge now though and he's got the "F", "C", "P" "S", and "T" calibrations currently - ebay.us/VqEbdY. Here's another I found - ebay.us/nud8nD. And on Amazon at amzn.to/484yUPY. Here's a third seller, selling refurbished "F" calibration air core motors - ebay.us/2SHX5a (remember anyone selling yellow plastic housing motors are selling used pulls or rebuilds, not NOS). I'll update this pin if the supply situation should change. Remember the used yellow original ones will not fix the needle dancing problem my video covers for the "F" or "C" fuel gauge air core motors, but the used yellow ones should be fine for the other gauges in "T" "V" "S" and "P" calibrations and to correct a completely inoperative / dead gauge situation.
DrShock I am going through a bunch of these 6.5 videos once again because my truck is broke down once again. I hate this truck. I really hope I can earn enough money to buy a new truck soon. Good video btw. If I cared about my truck, I would do this swap.
I'd like to add that we have remanufactured "f" motors and they are good to go. I have the original applicator to inject oem fluid into the motor. The "f" motors are permanently out of production. The remanufactured F motors are the only option now. Visit www.usdashworks.com to place your order.
I am having a different issue in my '94 Suburban. I can tell when the oil is getting low when the oil gauge starts twitching. I get low on oil quite often because I am using that special Mobile 1 0W-30 for better fuel economy. For the fuel gauge, I think it was not calibrated for the fuel tank. From the factory, it came with an optional 45 gallon tank. When the tank is full, the gauge goes way past the F line. The lower the gauge goes, the more accurate it becomes.
@@GeekBoy03 Past full line really sounds like a sender problem. This video might help - ruclips.net/video/dw9Hia55yys/видео.html as the test it covers is for both gas and diesel.
If you can find new replacement, the white ones will work for fuel level? I went to the junkyard and found a F gauge. And it had good resistance so I replaced it but it still vibrates. I adjusted the gauge as follows. And I also replaced the fuel pump. Due to a fuel sensor level code. So I’m sure the fuel pump sending unit was bad and the gauge was bad as well.
Watched this because I noticed a slight twitch in the fuel guage of the Tahoe I recently purchased. Literally the next time I started it, that puppy spun all the way around like that. Thank you!
FINALLY!!! A video that not only is exactly the issue I have,, but also a step by step as you "show" the steps where there are no gaps where I have to guess or wonder any of the steps, like other how too videos on here! Thank you for this video! I was about to replace the expensive sending unit! I woulda benn so pissssed to find that wasn't it!!! thank you!
In the future when the next gauge in your truck goes crazy twitching. Try using super lube silicone oil, used that on my fuel gauge it was doing the same thing, twitching and going crazy. The fuel gauge works like a damn now.
I had this fuel gauge problem in my 1999 suburban and its driving me crazy I did a lot of researches and many peoples were talking about changing the fuel pump clean the ground terminals taking the gauges out and clean it with alcohol its all worthless solutions , a close friend to me knows about me having this problem he sent me this video as Christmas gift I'm serious that was my Christmas gift and guess what its the best gift I ever got in my life because this video CLEARLY showing me the problem and how to fix it straight forward , Sir you saved me from getting rid of my 1999 rare Sony edition suburban .Thanks a lot and Merry Christmas .
Thank you, not only was this video very helpful, but for the most part it wasn't shot by you holding the camera in one hand while trying to do the repair with the other hand. So kudos to your camera person, and i wont even discuss video that are shot vertically.
Oh man, this was both hilarious ad informative. I just found a sealed and preserved GMC SUV cluster that hss a tach that goes to 6 whereas, my 1995 Yukon has one that goes only up to 5. So, I one found in a field out in the desert. The desert sands are used frequently by illegal trash people and the stolen vehicle mafia for parts dumping. It has sand inside it but I am still going to try it out. And here is shocking reason why: You see, I too am suffering from the painful and expensive disgrace of living with the embarrassment of having the insidious condition of The Fuel Gauge Twitch. Hiw much gas do I have left? Thats that little dials only purpose. To let me know that I could be stranded by you in 20 miles. Now I have to do the MGP math. Then remember my miles. Wow, fuel gauge, I never realized how much you really do for me. Thank you.
Temp gauge pegged itself at 260 the other day but the engine didn't seem unduly hot. Will investigate further but I bet it's going to be this. Thanks for the comprehensive video. UPDATE: Coolant gauge it turned out was fine. I fixed cooling problem. Fuel gauge has been a problem since I bought the truck and ran myself out of gas last week. Purchased a new motor called "Stepper motor - Air Core F motor" from AR Speedometer on Amazon and am currently installing it. Will update with results. ==================================================================================================================================== Motor is built as an air core motor, no gears. I installed motor and it seems to work correctly. Also included in packaging was return label for core. Motor was packaged _very_ carefully.
I have a 1999 Chevrolet Tahoe and my fuel gauge is at full tank when I have a quarter tank ,. Thanks to this video I have the link so know I can buy this part for my cluster.
Enjoy the coffee! Had to replace the gauge cluster stepper motors on my 2002 Buick LeSabre. The Buick's erratic oil pressure reading was just the sensor; same thing on my GMC. LeSabre fuel readings were the sending unit on fuel pump. Thanks for the videos.
Excellent video! I've watched it several times and feel confident I can finally fix my '99 Suburban after all. Thanks for sharing this video for all of us!
Did this to my '99 tahoe. Seems to be working so far. Tip: fill your tank full before. Don't try and fit every single drop in your tank. Just go the the standard first click at the pump. When you first turn it on, the fuel gauge should adjust itself to full, it is slow. Let it go for a minute or 2. Key off, adjust needle and do it again. Run it with the cover off for a little while and watch your gauge, make sure it continues to read correctly. Go to 3/4 tank, fill up. Do the math for your tank size and it should be good. After you verify, close it all up. Gauge motor delivered was about $104.
gm has a great reputation for faulty dash and electrical issues in the 90's and early 00's. just an fyi if the oil pressure sensor goes out in yours depending on if it shorts or loses connections it can peg or show zero. zero return reference from the sensor in my 92 causes it to peg out, just some food for thought. if the sensor in my 92 actually sends a zero signal it kills the fuel pump. i recently had it go bad and for a year it was pegged. replaced the sensor and away i went with finding other things that were bad too. This said one wire on my 92 goes through the fuel pump relay and back to the pcm, one of those is a fuseable link so if its damaged that can screw with readings too. Best thing to do pull the sensor and check the pressure manually, this will tell you if the gauge or wiring is the issue. If the oil pump really is bad and the sensor is working it will kill power to the fuel pump. If the cluster is screwing up it will still throw the check gauges but will never kill the engine.
@@DrShock interesting, I didn't know that but thanks for the info. I just wanted to share my recent experience with my 92. I had a 99 suburban with dash and fuel pump issues but the pump had power so it was a no brainier and the cluster has shitty grounds everywhere.
@@DrShock you wouldn't happen to know if these are the same motors in my 92 would you? i think the motor is weak, the oil pressure is different than the gauge according to my manual gauge i hooked up. it also doesn't come up with rpm increase sometimes but does other times and other times it drops to zero after its hot and then when i restart it goes higher but slowly drops back to zero. i suspect the motor is weak because it was pegged out for a while when the sensor was shot. i haven't torn it apart but i wondered if it was, thats actually what brought me to your videp
It's going to be the same aircore type gauge design, but I do not know if it's the same part used on the later models or not. Even the ones I did this video have had their supply dry up during the pandemic though. I pinned a comment at the top of a speedo shop on eBay that offers a rebuild service. You might ask those folks.
@@DrShock thanks, i appreciate your time.the salvage yard has a cluster so i might try my luck there. hoping my amazon oil pressure tester is right, i don't want to do an oil pump. the gauge is acting a bit strange, my only concern is when the gauge hits 0 oil the check gauges comes on but if i manually push it over it doesn't trigger the same warning. so i don't know if the gauge triggers that or the switch itself. not sure exactly how those operate but i will put this other cluster in and see what changes then swap the motor if thats it and keep the rest for future use if the motors are all gone. the yard only wants 50 for the whole cluster but who knows whats good in them. again thanks alot for your responses
Holy crap, no wonder my new fuel motor didn't work, I missed the crucial step of swapping over that tiny resister from the old motor. Too bad I had already thrown it away, but luckily I had just bought a parts cluster cheap for the temperature motor. Great video! Thanks
DrShock, I too get to do this with my truck sir. But, thanks again for sharing your knowledge and videos, it won’t be as hard as I thought it was going to be. Thanks again for sharing your videos so we all can learn something about our trucks or SUV’s.
I was going to buy one of these aircore motors on eBay, as suggested, and found one being offered by Digital Dash Solutions. Out of curiosity I Googled them, found their website, and saw that they were offering the same aircore motor that they're selling on eBay for less money, $30 instead of $44! So I ordered one from them, received it in California from Connecticut in a couple of days, and I just installed it yesterday. My old one had been doing the quivering thing and occasionally swinging wildly, then it would stay on "Full", so I couldn't mark the level as shown in the video. So I went and filled the tank, then set the needle on "Full". Now I'm going to have to drive around and see if the needle responds the way that it's supposed to...
Great video hope other people learn that you need a camera person to do this kinds of video and not trying to do everything with one hand love it I think I can take on my own instrument cluster thnx
Good thing you told us how to do the fuel gauge, cause that's the one you didn't say how to do other than to remember where it was but that kinda no help because it's erratic and who knows if its actually sitting at whatever. What if the gauge doesn't work? I guess I could fill the thing plum full probably be the only way.
LOVE YOUR VIDEO! DECENT INFO ON PROBLEMZ WITH THE GUAGEZ! I RESPECT THE TYME YOO TOOK TO LET OTHERZ KNOW WHAT COULD BE WRONG. KEEP UP THE GOOD WERK!! 👏🏼👏🏼😁😁👍🏼
Some of these are PC195 bulbs, there's a link in the description for them. The difference is that the bulb and socket are an integral part, rather than the bulb being separately replaceable. Once you see what they look like, you may be able to find an LED equivalent.
Informative video...thanks...I only wish people would check their volume when producing these vids...We can ALWAYS turn it down if it's too loud...lmao
A tip for those with a scanner that reads live engine and sensor data… including fuel level. I always connect my scanner with the cluster lens off so the needles are easily accessible. I watch the readings on my scanner versus what the cluster reads. If it reads a bit off, I shut off the vehicle and adjust the needles accordingly. I even test drive it to be sure the speedo is accurate. I hope this helps someone.
I have a 2000 Chevy 3500 with a 454 engine my fuel gauge stops reading at a half tank it will read full when filled it also seems like the needle vibrates when sitting still do you think it could be the gauge.
Vibrating needle problem is what this video was about, but reading wrong is more likely the sender. The linked video in the upper right of this one might help with that. I've seen both needing replacement with these OBS trucks being over two decades old now.
I have a 2000 obs 1ton classic My fuel gauge reads about half when it's a full tank. When the key is off it zeros out. Your video shows it doesn't go to zero/empty with the key off. I'm trying to re calibrate it too read full. I have a full tank now.
Yep I have a 98 Chevy Cheyenne 2500 5.7 and does this . My oil pressure gauge seems to work but my oil pressure isn't good when gets hot but my temp is off and my gas gauge is off
Nice video. I have two 98 chevrolet trucks. The half ton's gas gauge does not work and it usually reads completely full no matter how much gas is in it but will periodically drop down to empty and then go back to full. The needle also has a slight vibration to it so that it looks blurry when you look at it. I don't know if this is a sender issue, wiring issue or the gauge. The 1 ton's oil pressure gauge bounces around and always reads 80 psi initially. The volt gauge usually always reads low and my speedometer is off by about 5 mph. I would like to fix all of these issues but those motors are expensive so I may just have to live with bad gauges.
Thanks, the fuel gauge needle twitching/vibration is definitely the aircore motor itself and the subject of this video. But the gauge not working reliably, or at all, is more likely the sender in the tank. This other video I did was mainly for the diesel engine but the schematics and test process in the front are the same for gasoline. You might try this - ruclips.net/video/dw9Hia55yys/видео.html Since you have troubles with the fuel, oil pressure, speedometer and voltage gauges it's more likely a cluster issue than all of those individual aircore motors going out at once. If this were my situation, I would try an LKQ salvage yard and pull an used replacement cluster myself, keeping the gauges but transferring over the odometer from my original and seeing if I get better results.
@@DrShock Thanks for the reply and information. I will have to see if any of the salvage yards still have any clusters. The one ton truck with all of the cluster issues only has 119,000 miles on it .
ive looked everywhere for the tool u use to take the needles off cant find it anywhere must be a rare tool lol good vid thanks for the walk through. good info
The gauges and the trip on my 96 Tahoe are messed up too. According to the instrument cluster, my truck runs super cold, and I always have a full tank, except when I decelerate with about 1/4 of a tank.
First I wish to thank you for doing such a clear and detailed video. I have a few questions. At the 10:15 minute mark, you said that the fuel gauge will stay in its correct position when the power is turned off. My fuel pump quit working a few weeks ago and kept blowing fuses. When I changed the sending unit the wires on it were all melted and fused together. (I am lucky I didn't blow up.) After replacing the fuel sender my fuel gauge has been spinning wildly and jamming against the oil pressure gauge or stopping at random positions, so marking the position would not help since the needle always stops in a random position. Other than draining the gas tank to empty do you know a better way to find the correct position for the gauge needle? (Your video also showed me how to pull the dash so I can change all my burned-out lights...THANKS!)
Thanks, there's some more technical info in the video description too. But in this situation you have to manually recalibrate for empty and full. The easiest to do is full, as empty isn't really empty to help you get to a station you have some _reserve capacity_ even when it says E. So I would go for F instead, to start loosely install the needle, and fill her up. Then set the needle to where you usually saw the needle when doing a fill up (some will be slightly past F, some right on the money, and some a little ahead).
Good job bud......now I no wuts going on with my fuel gauge it flickers here and there .....I have 1997 gmc savana van. But it says gmc truck on the van. But verrrry helpful thank you
GM hasn't made new clusters for these trucks in many decades. There were some aftermarket rebuilt ones I linked in the description, but they do not always get the aircore motors replaced.
My gas gauge spun like a clock and just like you said it took out the oil pressure gauge. 99 k1500 5.7 suburban. Its a shame it went bad altho i had to replace the stepper motors in my 04 yukon 2 years ago. So it lasted longer (suburban) then the next generation factory replacement(yukon).
While the video is specific to the old body style (ended in 1999 for pick ups, 2000 for SUVs, and 2002 for 3500 commercial chassis cabs) C/K truck models, the same type of aircore motors were used on the G van, P van, and S/T trucks as well. They were used on the first couple of years of the new body style trucks as well.
WOW!! I wasn't looking for this video, but my RPM needle has just started to do this occasionally on my 92 Silverado. Thank you, and great job!! I know what to do for it now..👍
Wow, You have some great oil pressure on that 6.5L.. Must be really low mileage. My 6.5 is 195K and only puts out 25 at idle and north of 35 almost 40 when running down the road.
DrShock....... Great video....... I recently did the LED bulb conversion on both my 99 Z-71 and my 99 Tahoe. LED's do work great but the sockets that came with them did not line-up with the contacts so I just re-used the OEM sockets. Now if I am watching and hearing you correctly I don't really need to be too concerned with the positioning of the needles on the 4 gauges when re-installing the instrument cluster as once power is put to the cluster the inputs to the 4 Aircore motors will drive them to where they should be. I ask as I noticed needles moving all over as I was re-installing the instrument cluster but once back together and vehicle in operation they all appear to be where they should be. LoL.... I guess what I am really asking is as long as one doesnt mess with the needles or the motors there is no need to be worried about the needles floating around. Really good video, thanks.
Other than the fuel gauge and voltmeter, all the others start at zero on power up. So if you notice I have the key turned enough to power up the instrument cluster so I can verify all but the fuel and voltmeter are on zero. You do sometimes have to tweak them a bit, don't press the needles fully on the motor shafts until they are where they should be.
They are very popular, maybe these sellers should thank me for making this video ;-) I've seen them come and go out of stock a few times since making the video, I think these guys buy a batch from a China factory and then have a long lead time/delay before they can get another batch. That's just a guess but what it looks like. I would just keep an eBay saved search on them unti they have them back In a pinch you can use the "C" calibration which I mention in the description is calibrated for later year fuel senders but still "fits".
@@DrShock Might just be bad timing on my part as the vendor says that was the last batch that they will be selling but will do as you said in case that changes. Searched your other videos. I also have an issue with the temp gauge as it never goes higher than the big hashmark between 160'F and 210'F. Scanner reads the PCM Temp Switch at 194"F. So I disconnected Temp Gauge Switch , grounded the loop, turned the key on and it pegged out high as it should. Replaced the temp switch and now I got movement but after warming up goes to the big hashmark between 210 and 260 and sits there. Scanner reads PCM Temp Switch at 194'F. Just kind of odd the readings were initially low, replaced temp switch and now they are high going the other way. Uggh what a pisser feels like I am chasing my tail.
Wow I hope that's not the case for the "F" motors! On that temp gauge, the aircore motor movement is driven by the PCM sending a value to that circuit based on its read from the temp sender. In my experience the best accuracy is had with using genuine ACDelco parts or higher quality branded replacements. This is simply because the software in the PCM is calibrated to the GM part resistance and some cheaper brands don't feel the need to get it exactly the same. Usually I would point to that as something to check but since the PCM is reading the same consistently with two temp senders now, yet the gauge is reading differently without touching it I don't have a suggestion for you short of living with the previous sender as that was closer to the actual reading from the PCM. If it were me I'd put a new ACDelco sender on the engine, make sure PCM temperature readout was as expected, and then manually calibrate the gauge needle to where it should be. That might leave it off zero at cold but hopefully get it right for what counts.
I have a 97 Olds Cutlass Supreme SL. I removed the cluster to clean and repair the lights. I also painted the plastic frame where the lights are with a gloss white. Back together and reinstalled the cluster. Everything works great.... except the speedometer. When I turned the key on, the speedometer went to 10 mph. So I pulled the needle and set it back to zero against the stop pin. My problem is that it now reads anywhere between 8 to 10 mph too high when driving. Verified using my scanner to show VSS indicated speed, and a GPS mph app. Both read the same speed. Am I overlooking something? As usual, stuff was working fine except the lights before I did this. After 40 plus years of jet aircraft engine and sheet metal overhaul/repair and repairing cars since I was tall enough to see over the fenders stuff like this happens and it's annoying. The speedometer doesn't normally move when you turn the key on and after moving the needle from 10 to zero it hasn't moved when the key is turned on. It just reads too high when driving. I'm at a real loss here.
These components can be very fragile, age an all. I would be hazarding a guess. But _cleaning_ implies a chemical that may not be vintage electronics friendly. Either the aircore motor for the speedometer was damaged by the cleaning, or damaged when disturbed from it's original mount. Fortunately, these don't have the issue with internal dampening fluid that the fuel gauge aircores do, so a salvage yard donor should fix you up there if this is the case. I'd carefully inspect the flexible circuit board for no damage to the speedometer mounting area as well though.
@@DrShock Hey, thanks for the response. Actually it has a genuine circuit board. Phenolic material I think, but not a flexible one. I didn't touch the motors or board as far as cleaning went. However your points are well taken. Nothing to lose so I am going to try and reposition the needle at 25 or 30 mph indicated to what the scanner says actual is. (Front wheels off the ground). I'm like a kid in a candy store when I go the "pull-a-part" yards here. I have a spare cluster as well so if all else fails I will cann a motor from it. I will let you know how it goes.
Update: The adventure worked. Pulling the needle out and repositioning it to actual speed while the speedometer is running. Took two minutes and six tries. Lowered car back on the ground and road tested. Speedometer read correctly at all speeds comparing to scanner VSS speed and GPS MPH app. I suppose this is one way to do it. Could be pure luck also. Anyway, Thank you for the video and the help.
Nice video. But I suspect poor connections either at the main connection to the panel or at the plug-in to the circuit board. Crap connectors! Servicing it reset both of those, scraping the oxides off, and might have worked w/o the motor change. By the way, the motors are just a magnet attached to the needle shaft, set inside two coils of wire set at right angles; the circuit drives them with different currents to point the needles. You can measure resistance of the coils to test them and/or drive the needles to a known position by running current through a diagonal set of terminals from maybe 3V DC. Mark that and you can replace the needles to that position. Also, if you have sticking gauges, check that the needle's hubs are NOT dragging against the mask as they can easily do if pushed on too far. That made me crazy for years.
Thanks. But no, not a chance of electrical connectivity at issue here. The aircore motor is an analog device, being utilized to present a digital signal. To account for the mismatch, GM engineers specified the aircore motors calibration to also include a _dampening fluid_ to delay the needle response. This accounts for representing a digital square wave signal, until it dries out. The _fluttering_ is 100% due to loss of this dampening effect, which leaves the needle to portray the 1s and 0s of the digital square wave incorrectly in a naked un-dampened fashion. Some folks have tried manually re-injecting a silicone fluid in to replace the OEM dampening fluid, but this is at best a temporary mitigation. It _always_ returns. Replacing with an NOS aircore motor, or a professionally rebuilt one by a speedometer repair facility, is the only viable long term repair.
There are a few ebayers and shops that lubricate and/or rebuild these motors... I just sent a P motor to a rebuilder with an excellent rating. Let's see what happens. If it comes out well I will recommend them here. My cluster is from an 05 Chevy Astro.
I hope that I can find these motors, going to replace the factory radio while I have the bezel off , it still has the factory AM/FM Delco radio.. Any help locating these motors would be a help.
Supply from China has dried up. Pinned comment has the only source, an eBay seller, left who has some stock and original equipment to refurbish used motors as well.
From your commentary above: "If your gauge was very messed up you may be in the rare situation of not being able to perform the calibration procedure outlined in the video, in that situation you will have to get access to a new fuel tank sender, hook it up and use it to calibrate the empty, 1/2, and full positions accurately." My question is: If I get ahold of a new fuel tank sender in order to calibrate my gauge, how do I go about hooking it up? After installing my new aircore motor, I filled my tank, then set the needle to "Full". I've driven well over 100 miles, and the needle hasn't budged. I suspect that my fuel tank sending unit is probably bad, but I'd like to be able to confirm it.
You mentioned filling the tank, and then setting the needle to point to F. I presume you first set the needle where it was with the old aircore motor as shown in my video first. The vast majority of the time that should be enough. If you did and it was still off significantly, then yeah this additional calibration approach mentioned may be needed. But to do this accurately, you would have to have known how many total gallons used to set you at "F", or 1/2, in the past so you can drain the tank and add back checking E, 1/2, and finally F. What drives the aircore motor, and thus the fuel gauge needle, is a resistance reading coming in from the sender itself, this is within the wiring harness you connect to the sender unit (diesel) or fuel pump assy (gasoline). With a service manual, you might check that you're even getting that sender resistance value, and that the value is correctly changing with the fuel level in the tank. In fact a speedo shop would likely re-calibrate the E, 1/2, and F gauge readings after installing a new aircore motor solely on the bench from the resistance values for that particular model year.
@@DrShock I actually just today received a used instrument cluster that I got on eBay. I swapped it out an hour or so ago, and the needle went right to "Full", just like it does on the original cluster. Before I replaced the aircore motor, after doing its dancing, the old aircore's needle would settle on "Full", which is why I filled the tank and set the needle back on "Full". That's why I believe that the sending unit is bad.
On these years PRNDL part of the instrument cluster is fed range input by the park/neutral position transmission switch. I've not encountered this sort of issue before on the 90s trucks, but I would hazard a guess it could be a problem within that specific switch, or a problem getting voltage to the PRNDL circuitry of the cluster. You would have to get the service manual schematic and check each of the 4 switch outputs are making it to the IP cluster connector, then check that the lines for PRNDL voltage/dimming are making it. If those are good, it's a problem on the IP cluster circuit board itself.
These are the same air cores that were used in 99-02 gmt800's, the gmt800's didn't use resistors, but all gmt400's used resistors. And the old air cores are fine and do not need replacement, they need fresh dampening fluid put in them. Your fuel gauge jumps like that because your sender in the tank has bad spots in the reostat and the dampening fluid in your fuel gauge air core has gone bad allowing it to rapidly respond to any changes in the sender signal. You don't notice it with the new air core because it has fresh dampening fluid in it to slow the gauges movement covering up any fuel sloshing or slight irregularities in the sender signal. You could have accomplished the same thing with some 30k weight rc silicone diff fluid and a syringe.
That's partially correct, I explained some of the theory around this in the video description. The dampening fluid is used because of the waveform shape used on the PCM output for these years. Only a diesel engine has a direct sender to gauge circuit though. Unless you have the appropriate shop tooling that a cluster rebuild center would have, any attempt to syringe in fluid would be temporary at best. So replacement of the aircore motor is the only long term repair. Unfortunately that supply has been exhausted. Fortunately, you can have the aircore motors rebuilt still, the pinned comment lists a known cluster shop I've done business with who has the right equipment to rebuild them which would be as good as a new motor replacement.
@@DrShock My repaired clusters I've done for people, including my own, are all still going years later after I redampened them. And only 98+ gas engines ran the fuel gauge through the pcm(97 V6's used a fuel gauge module), all 97 and older V8's, 96- V6, and all diesels(unless it had dual tanks) ran the sender direct to the fuel gauge. All oil senders go direct to the gauge.
@the section about the bulbs , these are all 194's? I assume these are clear bulbs wondering if I decided to use maybe blue if it would affect the orange needles..
So I have a 97. 5.7. Obs; the old thermostat would keep the truck running cool around 145. The temperature gauge in the cluster read that temperature accurate. However, when I put in a new thermostat. That brings the truck operating temperature. Once it hits 150 it just keeps going all the way to 240. I’m gonna check all my grounds.
I cant find it with the letter F for the fuel they start with the letter C for the fuel. I have a 1994 chevy blazer k1500, and excellent video by the way.
Yeah it seems the Chinese suppliers of the "F" type motors are either backordered or the supply has ran out affecting what's available on eBay currently. Personally I'm waiting a bit longer to see if the "F" type comes back in stock with the larger eBay sellers because "C" certainly isn't the original calibration. But if "F" is gone for good, "C" might have to be the next best substitute going forward. These trucks are coming up on 30 years soon so not that surprising parts availability wise.
A speedometer shop on eBay is now selling these again, but he's only got the "C", "P" "S", and "T" calibrations currently. I put a link in the description.
I have a bouncing fuel gauge that I assume has to do with a broken slosh baffle in the tank. I haven't checked to confirm but now I'm wondering if it's the same cause as this one.
Dr. Shock como siempre muy buenos vídeos tutoriales, específicos y educativos. Quería hacerle una pregunta muy específica al tema: Resulta ser que hace unos días desarme el panel de instrumentos de mi tablero del coche. Para remplazar unos Light bulb fui muy cuidadoso aproveche para limpiar instrument cluster connector tanto en macho como la hembra con un cotton tip y alcohol isopropílico (ya que veían con algo sucios y con polvo). Antes de volver a montar instrument cluster; Después hice mis pruebas abrí la llave ignición todas sus luces bien, gauges bien, selector de cambios prnd123 bien. Y al cerrar la llave de encendido. Probar la iluminación, encendido los tail light Hooo! Sorpresa 😭. El gauges del oil y fuel se mueven a la posición cero más que nada el del oil y si enciendo el motor y Luego tail light veo como el medidor se mueve una un poco hacia cero o empty pero como la señal del ops o fuel sender unit son más fuertes pues no se va a 0 psi. Buscando información en internet me topé con tu vídeo ruclips.net/video/dw9Hia55yys/видео.html. El cual me ayudó mucho vi instrument cluster connector en esos diagramas pude identificar cada pin (porcierto que libro usas, ya que aquí en México no es fácil encontrar esa información) Me topé que el pin 29 es el de las iluminación dimming del señal tail light y hay 2 ground el pin4 que es para la electrónica del cluster y el pin 31 que es para bulb light y Gnd de los gauges veo que se comparten. Use mi multímetro para medir resistencia y noto que midiendo el pin 4 a cualquier metal expuesto e la carrocería hay una resistencia de 20 ohms yo deduzco que a de ser la vejez de cable pues 22años. Pero yo le pregunto sabe usted si el Gnd del cluster tiene alguna resistencia de paso como protección. O va directamente al chassis y si para estos cluster es despreciable eso 20ohms en el conductor o recomienda reemplazarlo el cable para bajarlo a menos
Mucha información aquí, intentaré abordar la que tienes. - Debe tener cuidado con los solventes en una placa de circuito impreso de mylar flexible como la que se usa en el grupo de instrumentos. Puede dañar el plástico en algunas formulaciones. - Sí, las bombillas de repuesto de la marca del mercado de accesorios pueden tener problemas para hacer contacto con la placa de circuito impreso flexible. Puede levantar, ligeramente, las clavijas de contacto de los portalámparas con cierre giratorio. - Estoy usando el manual de servicio de camiones GM genuino de 1998, que ha estado agotado durante más de una década. - No estoy familiarizado con todos los circuitos de tierra involucrados en el esquema del grupo de instrumentos. Pero suena como un problema de fondo que está describiendo allí. A lot of info here, I’ll try and address what you have. - You have to be careful with solvents on a flexible mylar printed circuit board like that used on the instrument cluster. It can damage the plastic in some formulations. - Yes, aftermarket brand replacement bulbs can have trouble making contact on the flexible printed circuit board. You can pry up, slightly, the contact pins on the twist lock bulb holders. - I’m using the genuine GM truck service manual for 1998, which has been out of print for over a decade now. - I’m not familiar with all of the ground circuits involved in the instrument cluster schematic. But it does sound like a ground problem you are describing there.
@@DrShock muchas gracias Dr. Shock , no sabe cómo. El manual de reparación de la GM que tiene se le puede comparar con libro CHILTON 28624, o nada que ver el original siempre será más completo??? Para concluir podría hacerme un favor : en su otro vídeo muestra en su manual GM en la hoja del : "instrument cluster connector" Que el pin 4 y 31 que comparten Gnd menciona que revise el circuito N° 451 de su libro. Agradecería si me mencionara si el cable va directo y atornillado alguna parte metálica carrocería o chasis y porque área aproximadamente se puede encontrar esa conexión en la cabina o si pasa por algún circuito de protección y por eso la pequeña resistencia. Dr. Shock de lo demás yo me encargaría e investigaría. De antemano gracias.
He utilizado guías de Chilton para vehículos en los que no tengo el manual de GM a mano. Ciertamente son buenos libros y los recomendaría. Pero no puedo decir si la camioneta de este año tiene lo que está buscando esquemáticamente. No he tenido que depurar el circuito de tierra del grupo de instrumentos, así que no puedo decirlo. Pero conecte a tierra cualquier circuito de tierra 4xx (por ejemplo, 451) que se ubicará en el área de la caja de la rueda trasera / cama. I have used Chilton guides for vehicles where I don’t have the GM manual handy. They are certainly good books and I would recommend them. But I can’t say whether the one for this year truck has what you’re looking for schematic wise. I haven’t had to debug the instrument cluster ground circuit, so couldn’t say. But ground any 4xx ground circuit (e.g., 451) is going to be located in the rear wheel house/bed area.
I have a 2wd Suburban with barn doors and no fog lights, but all those plugs are there behind the cluster bezel. I guess they used one harness for all their trucks.
Great video! I changed the motor with a new one. Included the resistor and the motor is making a buzzing sound. I replaced the sending unit and fuel pump and still the same issue. I even tried a used stepper (F) motor from a different dash. Guys - I’d appreciate any thoughts on where to go next. Thanks!
And even the original motor was buzzing? If not, was the motivation to replace it due to the needle dance problem alone? My first reaction with this symptom is a wiring problem heading into the cluster, but the original aircore motor should have exhibited the same noise.
The original motor had a very faint buzz to it but almost inaudible. I placed my finger on the stem and could feel it vibrating. The new motor was more amplified and also vibrating. The idea was to correct the vibrating fuel gauge and fix the random intermittent fuel reading. Most of the time it would read correct and then randomly show empty or a full tank and stay there for some time. Thank you for your questions and trying to help. I’ll get under the truck and follow the wiring harness this weekend and see if I can find anything.
My gas gauge works fine,but it moves back and forth about 1/8 in when my turn signal is on. I think it has something to do with using heavy duty flashers. It never did that until I installed those.
Now I know how to disable the ABS light and service 4wd light. No front half shafts or drive shaft. Pulled the ABS fuse because I almost ran into the house because the ABS decided to wig out on me on dry pavement.
Normally the only issues with abs on these trucks is the front hub sensors. The hub rusts and the sensor is a magnet. So it flakes off and sticks to the sensor. If there seized in there just buy new ones if not pull them out clean off the crap and plug your fuse back in.
Enjoyed this video. Have you thought about going digital instead of analog? Had the same issue with my vehicle then decided to replace the gauges with digital.
Both the fuel gauge and water temperature Guage in my motorhome are stuck. I'm going to use your techniques to fix them. RV mechanics charge huge fees for repairs.
One indication it's a grounding issue is when two or more gauges dance similarly. For the last year or so, my old 1993 C1500 was exhibiting the issue. I pulled the gauge cluster and cleaned all the electrical trace push-in electrical connections. I installed brand new lighting bulbs too! The problem didn't disappear. Eventually, I started having symptoms of the engine and transmission dropping out for moments. Then, the engine really started cutting out and bucking. Okay, I guess I gotta do something real about the issue now... Powers and grounds, it's always powers and grounds. In the engine bay right behind the alternator, there are two studs about 4" apart. Each stud grounds two wires. The terminating lug at each connection was a green creepy crusty mess. I cut the wires back a bit, soldered in new wire lengths, soldered in a new grounding lug, heat shrink tubing everything, cleaned up the stud mating surfaces with a wire brush cup on a Dremel, and reassembled everything. The gauge jitter mostly disappeared and the 5.7l V8 is back to its sewing machine smoothness. One issue remains, however, The volt meter drops from a reading of 14 to 10 and back to 14 when the turn signal flasher is operating. So, should we get a comfortable day temperature and dryness wise, I'm going to refresh the grounding terminations for the front and rear turn signal circuits. Powers and grounds, it's always the first thing to verify and check!
You could start here on the grounds, ruclips.net/video/H0lK0TZEVCc/видео.html What's shown in this aircore motor video isn't ground related behavior, but it is a good checklist item to start with.
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PSA: Guys the supply of these replacement Air Core Motors seems to have dried up and they are much harder to find now. Several links here and in the video description text to help you though. Try all of the links on both eBay and Amazon to find the best price for the calibration(s) you need.
They were available for a time as outfits like Dorman that were remanufacturing these dash clusters, as well as local speedometer repair shops, provided enough demand to warrant producing them still. But as of March 12, 2020 they are basically in the new old stock (NOS) stage now and every one of them will be an easter egg hunt. The "F" calibration is the hardest to obtain now, I see only two sellers on eBay affiliate linked below:
One seller on eBay, USDashWorks, who is selling the actual units I have bought in the past, has them back in stock. They have a core charge now though and he's got the "F", "C", "P" "S", and "T" calibrations currently - ebay.us/VqEbdY. Here's another I found - ebay.us/nud8nD. And on Amazon at amzn.to/484yUPY. Here's a third seller, selling refurbished "F" calibration air core motors - ebay.us/2SHX5a (remember anyone selling yellow plastic housing motors are selling used pulls or rebuilds, not NOS).
I'll update this pin if the supply situation should change. Remember the used yellow original ones will not fix the needle dancing problem my video covers for the "F" or "C" fuel gauge air core motors, but the used yellow ones should be fine for the other gauges in "T" "V" "S" and "P" calibrations and to correct a completely inoperative / dead gauge situation.
DrShock I am going through a bunch of these 6.5 videos once again because my truck is broke down once again. I hate this truck. I really hope I can earn enough money to buy a new truck soon. Good video btw. If I cared about my truck, I would do this swap.
I'd like to add that we have remanufactured "f" motors and they are good to go. I have the original applicator to inject oem fluid into the motor. The "f" motors are permanently out of production. The remanufactured F motors are the only option now. Visit www.usdashworks.com to place your order.
I am having a different issue in my '94 Suburban. I can tell when the oil is getting low when the oil gauge starts twitching. I get low on oil quite often because I am using that special Mobile 1 0W-30 for better fuel economy. For the fuel gauge, I think it was not calibrated for the fuel tank. From the factory, it came with an optional 45 gallon tank. When the tank is full, the gauge goes way past the F line. The lower the gauge goes, the more accurate it becomes.
@@GeekBoy03 Past full line really sounds like a sender problem. This video might help - ruclips.net/video/dw9Hia55yys/видео.html as the test it covers is for both gas and diesel.
If you can find new replacement, the white ones will work for fuel level? I went to the junkyard and found a F gauge. And it had good resistance so I replaced it but it still vibrates. I adjusted the gauge as follows. And I also replaced the fuel pump. Due to a fuel sensor level code. So I’m sure the fuel pump sending unit was bad and the gauge was bad as well.
Watched this because I noticed a slight twitch in the fuel guage of the Tahoe I recently purchased. Literally the next time I started it, that puppy spun all the way around like that. Thank you!
FINALLY!!! A video that not only is exactly the issue I have,, but also a step by step as you "show" the steps where there are no gaps where I have to guess or wonder any of the steps, like other how too videos on here! Thank you for this video! I was about to replace the expensive sending unit! I woulda benn so pissssed to find that wasn't it!!! thank you!
In the future when the next gauge in your truck goes crazy twitching. Try using super lube silicone oil, used that on my fuel gauge it was doing the same thing, twitching and going crazy. The fuel gauge works like a damn now.
I had this fuel gauge problem in my 1999 suburban and its driving me crazy I did a lot of researches and many peoples were talking about changing the fuel pump clean the ground terminals taking the gauges out and clean it with alcohol its all worthless solutions , a close friend to me knows about me having this problem he sent me this video as Christmas gift I'm serious that was my Christmas gift and guess what its the best gift I ever got in my life because this video CLEARLY showing me the problem and how to fix it straight forward , Sir you saved me from getting rid of my 1999 rare Sony edition suburban .Thanks a lot and Merry Christmas .
That's great Merry Christmas! Here's another one, as sometimes this behavior can be the fuel sender too - ruclips.net/video/dw9Hia55yys/видео.html
None of us could ever be expected to be able to do this without your outstanding video! Thank you so much!
Great video. You have helped a lot of people with this problem. I am one of them. Thank you.
me too!
Got my air motor back from the eBay repair guy and it works great! BTW, it doesn't matter how you put on the needles, the air motors self calibrate.
Thank you, not only was this video very helpful, but for the most part it wasn't shot by you holding the camera in one hand while trying to do the repair with the other hand. So kudos to your camera person, and i wont even discuss video that are shot vertically.
Whoa. That's really great.
Man u have the perfect voice for narrative informational videos. It's like it's easier to absorb knowledge fromya
Oh man, this was both hilarious ad informative. I just found a sealed and preserved GMC SUV cluster that hss a tach that goes to 6 whereas, my 1995 Yukon has one that goes only up to 5. So, I one found in a field out in the desert. The desert sands are used frequently by illegal trash people and the stolen vehicle mafia for parts dumping. It has sand inside it but I am still going to try it out. And here is shocking reason why: You see,
I too am suffering from the painful and expensive disgrace of living with the embarrassment of having the insidious condition of The Fuel Gauge Twitch. Hiw much gas do I have left? Thats that little dials only purpose. To let me know that I could be stranded by you in 20 miles. Now I have to do the MGP math. Then remember my miles. Wow, fuel gauge, I never realized how much you really do for me. Thank you.
Temp gauge pegged itself at 260 the other day but the engine didn't seem unduly hot. Will investigate further but I bet it's going to be this. Thanks for the comprehensive video.
UPDATE: Coolant gauge it turned out was fine. I fixed cooling problem. Fuel gauge has been a problem since I bought the truck and ran myself out of gas last week. Purchased a new motor called "Stepper motor - Air Core F motor" from AR Speedometer on Amazon and am currently installing it. Will update with results.
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Motor is built as an air core motor, no gears. I installed motor and it seems to work correctly. Also included in packaging was return label for core. Motor was packaged _very_ carefully.
AWESOME! I have the same issue. Been trying to figure out what is wrong with my gas gauge for years. Thanks!
I HAD THE SAME PROBLEM A YEAR AGO REPLACED THE FUEL PUMP FIXED IT,ON 1998 GMC SIERRA EXTENDED PU 5.7L
I have a 1999 Chevrolet Tahoe and my fuel gauge is at full tank when I have a quarter tank ,. Thanks to this video I have the link so know I can buy this part for my cluster.
Enjoy the coffee! Had to replace the gauge cluster stepper motors on my 2002 Buick LeSabre. The Buick's erratic oil pressure reading was just the sensor; same thing on my GMC. LeSabre fuel readings were the sending unit on fuel pump. Thanks for the videos.
Excellent video! I've watched it several times and feel confident I can finally fix my '99 Suburban after all. Thanks for sharing this video for all of us!
Did this to my '99 tahoe. Seems to be working so far. Tip: fill your tank full before. Don't try and fit every single drop in your tank. Just go the the standard first click at the pump.
When you first turn it on, the fuel gauge should adjust itself to full, it is slow. Let it go for a minute or 2. Key off, adjust needle and do it again. Run it with the cover off for a little while and watch your gauge, make sure it continues to read correctly. Go to 3/4 tank, fill up. Do the math for your tank size and it should be good. After you verify, close it all up. Gauge motor delivered was about $104.
Whereabouts did you purchase the gauge from?do you have part number?
Just finished my part now next step will be installing everything back and see it working back to normal
My 1996 gas fueled Tahoe has the same issue. I find it interesting a diesel would also have the same issue. Thanks for posting!
gm has a great reputation for faulty dash and electrical issues in the 90's and early 00's. just an fyi if the oil pressure sensor goes out in yours depending on if it shorts or loses connections it can peg or show zero. zero return reference from the sensor in my 92 causes it to peg out, just some food for thought. if the sensor in my 92 actually sends a zero signal it kills the fuel pump. i recently had it go bad and for a year it was pegged. replaced the sensor and away i went with finding other things that were bad too. This said one wire on my 92 goes through the fuel pump relay and back to the pcm, one of those is a fuseable link so if its damaged that can screw with readings too. Best thing to do pull the sensor and check the pressure manually, this will tell you if the gauge or wiring is the issue. If the oil pump really is bad and the sensor is working it will kill power to the fuel pump. If the cluster is screwing up it will still throw the check gauges but will never kill the engine.
Thanks, good points. FYI that GM safety design ended in 1995. The oil pressure sender from 96+ is no longer involved in the fuel lift pump circuit.
@@DrShock interesting, I didn't know that but thanks for the info. I just wanted to share my recent experience with my 92. I had a 99 suburban with dash and fuel pump issues but the pump had power so it was a no brainier and the cluster has shitty grounds everywhere.
@@DrShock you wouldn't happen to know if these are the same motors in my 92 would you? i think the motor is weak, the oil pressure is different than the gauge according to my manual gauge i hooked up. it also doesn't come up with rpm increase sometimes but does other times and other times it drops to zero after its hot and then when i restart it goes higher but slowly drops back to zero. i suspect the motor is weak because it was pegged out for a while when the sensor was shot. i haven't torn it apart but i wondered if it was, thats actually what brought me to your videp
It's going to be the same aircore type gauge design, but I do not know if it's the same part used on the later models or not. Even the ones I did this video have had their supply dry up during the pandemic though. I pinned a comment at the top of a speedo shop on eBay that offers a rebuild service. You might ask those folks.
@@DrShock thanks, i appreciate your time.the salvage yard has a cluster so i might try my luck there. hoping my amazon oil pressure tester is right, i don't want to do an oil pump. the gauge is acting a bit strange, my only concern is when the gauge hits 0 oil the check gauges comes on but if i manually push it over it doesn't trigger the same warning. so i don't know if the gauge triggers that or the switch itself. not sure exactly how those operate but i will put this other cluster in and see what changes then swap the motor if thats it and keep the rest for future use if the motors are all gone. the yard only wants 50 for the whole cluster but who knows whats good in them.
again thanks alot for your responses
You saved me from pulling the tank on my Suburban. Thank you.
I have a 99 gas suburban. Did that fix your issue
Holy crap, no wonder my new fuel motor didn't work, I missed the crucial step of swapping over that tiny resister from the old motor. Too bad I had already thrown it away, but luckily I had just bought a parts cluster cheap for the temperature motor. Great video! Thanks
My temp Guage is acting funky too I changed both sensors already too
DrShock, I too get to do this with my truck sir. But, thanks again for sharing your knowledge and videos, it won’t be as hard as I thought it was going to be. Thanks again for sharing your videos so we all can learn something about our trucks or SUV’s.
Great video! My fuel gauge is starting to develop this problem so now I know what to do to fix it.
Thanks for the video! I just bought a 97 yukon GT two door, and the fuel and oil gauges fluctuate. Hopefully now I'll get it sorted.
Great video bud!!!!!! I’ve done these before and just bought an old truck for myself. Needed a refresher… thanks! Subscribed!
Thank god for smart people 🙏. Thank you
I was going to buy one of these aircore motors on eBay, as suggested, and found one being offered by Digital Dash Solutions. Out of curiosity I Googled them, found their website, and saw that they were offering the same aircore motor that they're selling on eBay for less money, $30 instead of $44! So I ordered one from them, received it in California from Connecticut in a couple of days, and I just installed it yesterday. My old one had been doing the quivering thing and occasionally swinging wildly, then it would stay on "Full", so I couldn't mark the level as shown in the video. So I went and filled the tank, then set the needle on "Full". Now I'm going to have to drive around and see if the needle responds the way that it's supposed to...
Darrin De May did it work out for you?
Thanks!! My 97 Yukon fuel gauge has the shakes!! Keep up the good work with the videos 💪🏾
Wow glad I found this video, my 1999 suburban fuel gauge is doing the same thing, I was dreading dropping the 42 gallon tank but will try this first.
I really find your videos on these trucks really helpful thank you
Thank you for sharing your knowledge, this is exactly what needs to be done to my 98 truck and dads 99 tahoe.
Thanks for the video! Definitely saved me some time! No more vibrating fuel gauge!
Great video hope other people learn that you need a camera person to do this kinds of video and not trying to do everything with one hand love it I think I can take on my own instrument cluster thnx
Good thing you told us how to do the fuel gauge, cause that's the one you didn't say how to do other than to remember where it was but that kinda no help because it's erratic and who knows if its actually sitting at whatever. What if the gauge doesn't work? I guess I could fill the thing plum full probably be the only way.
Wow! that's exactly what's wrong with my fuel gauge. Thank you save me possible 500 to a grand.
LOVE YOUR VIDEO! DECENT INFO ON PROBLEMZ WITH THE GUAGEZ! I RESPECT THE TYME YOO TOOK TO LET OTHERZ KNOW WHAT COULD BE WRONG. KEEP UP THE GOOD WERK!! 👏🏼👏🏼😁😁👍🏼
I appreciate you looking at your video and coming back to clarify.
How many 194 bulbs are replaceable? Want to install LEDs. Pleas advise. I have changed two motors. Great video.
Some of these are PC195 bulbs, there's a link in the description for them. The difference is that the bulb and socket are an integral part, rather than the bulb being separately replaceable. Once you see what they look like, you may be able to find an LED equivalent.
ive got an astrovan does the same gauge fluctuation was told sending unit in tank now ill replace this unit first thanks for this video
Informative video...thanks...I only wish people would check their volume when producing these vids...We can ALWAYS turn it down if it's too loud...lmao
A tip for those with a scanner that reads live engine and sensor data… including fuel level. I always connect my scanner with the cluster lens off so the needles are easily accessible. I watch the readings on my scanner versus what the cluster reads. If it reads a bit off, I shut off the vehicle and adjust the needles accordingly. I even test drive it to be sure the speedo is accurate. I hope this helps someone.
Just repaired my Safari using this video. Thanks
I have a 2000 Chevy 3500 with a 454 engine my fuel gauge stops reading at a half tank it will read full when filled it also seems like the needle vibrates when sitting still do you think it could be the gauge.
Vibrating needle problem is what this video was about, but reading wrong is more likely the sender. The linked video in the upper right of this one might help with that. I've seen both needing replacement with these OBS trucks being over two decades old now.
I have a 2000 obs 1ton classic
My fuel gauge reads about half when it's a full tank. When the key is off it zeros out. Your video shows it doesn't go to zero/empty with the key off. I'm trying to re calibrate it too read full. I have a full tank now.
Yep I have a 98 Chevy Cheyenne 2500 5.7 and does this . My oil pressure gauge seems to work but my oil pressure isn't good when gets hot but my temp is off and my gas gauge is off
Perfect!
Yukon getting and trying to keep together because I still like it. Was able to do with your video help. Thank you.
Yess!! My oil gauge does this andy fuel as well!! It causes it to pop up a check gauges light and causes it to idle.rough
If you're getting a service engine light, it's not the gauge but rather a genuine engine issue you need to get diagnosed.
Well off to the internet to get new guages. Good video.
I just learned the truck had a cup holder.
Nice video. I have two 98 chevrolet trucks. The half ton's gas gauge does not work and it usually reads completely full no matter how much gas is in it but will periodically drop down to empty and then go back to full. The needle also has a slight vibration to it so that it looks blurry when you look at it. I don't know if this is a sender issue, wiring issue or the gauge.
The 1 ton's oil pressure gauge bounces around and always reads 80 psi initially. The volt gauge usually always reads low and my speedometer is off by about 5 mph. I would like to fix all of these issues but those motors are expensive so I may just have to live with bad gauges.
Thanks, the fuel gauge needle twitching/vibration is definitely the aircore motor itself and the subject of this video. But the gauge not working reliably, or at all, is more likely the sender in the tank. This other video I did was mainly for the diesel engine but the schematics and test process in the front are the same for gasoline. You might try this - ruclips.net/video/dw9Hia55yys/видео.html
Since you have troubles with the fuel, oil pressure, speedometer and voltage gauges it's more likely a cluster issue than all of those individual aircore motors going out at once. If this were my situation, I would try an LKQ salvage yard and pull an used replacement cluster myself, keeping the gauges but transferring over the odometer from my original and seeing if I get better results.
@@DrShock Thanks for the reply and information. I will have to see if any of the salvage yards still have any clusters. The one ton truck with all of the cluster issues only has 119,000 miles on it .
ive looked everywhere for the tool u use to take the needles off cant find it anywhere must be a rare tool lol good vid thanks for the walk through. good info
Yeah super rare to have one clean for this application, if you mean at 12:33 it is the highly useful forkomatic from Chick-Fil-A. ;-)
Wow never expected to find this video thank you so much blessing 😊
Finally I found what I need. Thank you.
The gauges and the trip on my 96 Tahoe are messed up too. According to the instrument cluster, my truck runs super cold, and I always have a full tank, except when I decelerate with about 1/4 of a tank.
Excellent video, It was very informative and I think i will be able to fix my fuel gauge now.💪🏾
First I wish to thank you for doing such a clear and detailed video. I have a few questions.
At the 10:15 minute mark, you said that the fuel gauge will stay in its correct position when the power is turned off. My fuel pump quit working a few weeks ago and kept blowing fuses. When I changed the sending unit the wires on it were all melted and fused together. (I am lucky I didn't blow up.) After replacing the fuel sender my fuel gauge has been spinning wildly and jamming against the oil pressure gauge or stopping at random positions, so marking the position would not help since the needle always stops in a random position. Other than draining the gas tank to empty do you know a better way to find the correct position for the gauge needle? (Your video also showed me how to pull the dash so I can change all my burned-out lights...THANKS!)
Thanks, there's some more technical info in the video description too. But in this situation you have to manually recalibrate for empty and full. The easiest to do is full, as empty isn't really empty to help you get to a station you have some _reserve capacity_ even when it says E. So I would go for F instead, to start loosely install the needle, and fill her up. Then set the needle to where you usually saw the needle when doing a fill up (some will be slightly past F, some right on the money, and some a little ahead).
If they melted you may have a ground that is loose. Check all your grounds.
Excellent video, thanks for posting it and the link!!
Good job bud......now I no wuts going on with my fuel gauge it flickers here and there .....I have 1997 gmc savana van. But it says gmc truck on the van. But verrrry helpful thank you
Can you do a video on the 89’s on why the gauges would stop working and also how to fix fuel gauge flopping around on that year too?
Would installing a new cluster assembly fix the issue as well?
GM hasn't made new clusters for these trucks in many decades. There were some aftermarket rebuilt ones I linked in the description, but they do not always get the aircore motors replaced.
I have a 1993 Chevy diesel. Is it pretty much the same procedure. Also are the parts the same.
My gas gauge spun like a clock and just like you said it took out the oil pressure gauge. 99 k1500 5.7 suburban. Its a shame it went bad altho i had to replace the stepper motors in my 04 yukon 2 years ago. So it lasted longer (suburban) then the next generation factory replacement(yukon).
Outstanding Video. Are all the gages for these models 1994 - 2002 GM ?
While the video is specific to the old body style (ended in 1999 for pick ups, 2000 for SUVs, and 2002 for 3500 commercial chassis cabs) C/K truck models, the same type of aircore motors were used on the G van, P van, and S/T trucks as well. They were used on the first couple of years of the new body style trucks as well.
WOW!! I wasn't looking for this video, but my RPM needle has just started to do this occasionally on my 92 Silverado. Thank you, and great job!! I know what to do for it now..👍
Wow, You have some great oil pressure on that 6.5L.. Must be really low mileage. My 6.5 is 195K and only puts out 25 at idle and north of 35 almost 40 when running down the road.
DrShock....... Great video....... I recently did the LED bulb conversion on both my 99 Z-71 and my 99 Tahoe. LED's do work great but the sockets that came with them did not line-up with the contacts so I just re-used the OEM sockets.
Now if I am watching and hearing you correctly I don't really need to be too concerned with the positioning of the needles on the 4 gauges when re-installing the instrument cluster as once power is put to the cluster the inputs to the 4 Aircore motors will drive them to where they should be. I ask as I noticed needles moving all over as I was re-installing the instrument cluster but once back together and vehicle in operation they all appear to be where they should be. LoL.... I guess what I am really asking is as long as one doesnt mess with the needles or the motors there is no need to be worried about the needles floating around.
Really good video, thanks.
Other than the fuel gauge and voltmeter, all the others start at zero on power up. So if you notice I have the key turned enough to power up the instrument cluster so I can verify all but the fuel and voltmeter are on zero. You do sometimes have to tweak them a bit, don't press the needles fully on the motor shafts until they are where they should be.
Thanks for the update much appreciated. I followed your link but unfortunately the "F" Aircore are out of stock and may no longer be available.
They are very popular, maybe these sellers should thank me for making this video ;-) I've seen them come and go out of stock a few times since making the video, I think these guys buy a batch from a China factory and then have a long lead time/delay before they can get another batch. That's just a guess but what it looks like. I would just keep an eBay saved search on them unti they have them back In a pinch you can use the "C" calibration which I mention in the description is calibrated for later year fuel senders but still "fits".
@@DrShock Might just be bad timing on my part as the vendor says that was the last batch that they will be selling but will do as you said in case that changes.
Searched your other videos. I also have an issue with the temp gauge as it never goes higher than the big hashmark between 160'F and 210'F. Scanner reads the PCM Temp Switch at 194"F. So I disconnected Temp Gauge Switch , grounded the loop, turned the key on and it pegged out high as it should. Replaced the temp switch and now I got movement but after warming up goes to the big hashmark between 210 and 260 and sits there. Scanner reads PCM Temp Switch at 194'F. Just kind of odd the readings were initially low, replaced temp switch and now they are high going the other way. Uggh what a pisser feels like I am chasing my tail.
Wow I hope that's not the case for the "F" motors! On that temp gauge, the aircore motor movement is driven by the PCM sending a value to that circuit based on its read from the temp sender. In my experience the best accuracy is had with using genuine ACDelco parts or higher quality branded replacements. This is simply because the software in the PCM is calibrated to the GM part resistance and some cheaper brands don't feel the need to get it exactly the same. Usually I would point to that as something to check but since the PCM is reading the same consistently with two temp senders now, yet the gauge is reading differently without touching it I don't have a suggestion for you short of living with the previous sender as that was closer to the actual reading from the PCM. If it were me I'd put a new ACDelco sender on the engine, make sure PCM temperature readout was as expected, and then manually calibrate the gauge needle to where it should be. That might leave it off zero at cold but hopefully get it right for what counts.
I have a 97 Olds Cutlass Supreme SL. I removed the cluster to clean and repair the lights. I also painted the plastic frame where the lights are with a gloss white. Back together and reinstalled the cluster. Everything works great.... except the speedometer. When I turned the key on, the speedometer went to 10 mph. So I pulled the needle and set it back to zero against the stop pin. My problem is that it now reads anywhere between 8 to 10 mph too high when driving. Verified using my scanner to show VSS indicated speed, and a GPS mph app. Both read the same speed. Am I overlooking something? As usual, stuff was working fine except the lights before I did this. After 40 plus years of jet aircraft engine and sheet metal overhaul/repair and repairing cars since I was tall enough to see over the fenders stuff like this happens and it's annoying. The speedometer doesn't normally move when you turn the key on and after moving the needle from 10 to zero it hasn't moved when the key is turned on. It just reads too high when driving. I'm at a real loss here.
These components can be very fragile, age an all. I would be hazarding a guess. But _cleaning_ implies a chemical that may not be vintage electronics friendly. Either the aircore motor for the speedometer was damaged by the cleaning, or damaged when disturbed from it's original mount. Fortunately, these don't have the issue with internal dampening fluid that the fuel gauge aircores do, so a salvage yard donor should fix you up there if this is the case. I'd carefully inspect the flexible circuit board for no damage to the speedometer mounting area as well though.
@@DrShock Hey, thanks for the response. Actually it has a genuine circuit board. Phenolic material I think, but not a flexible one. I didn't touch the motors or board as far as cleaning went. However your points are well taken. Nothing to lose so I am going to try and reposition the needle at 25 or 30 mph indicated to what the scanner says actual is. (Front wheels off the ground). I'm like a kid in a candy store when I go the "pull-a-part" yards here. I have a spare cluster as well so if all else fails I will cann a motor from it. I will let you know how it goes.
Update: The adventure worked. Pulling the needle out and repositioning it to actual speed while the speedometer is running. Took two minutes and six tries. Lowered car back on the ground and road tested. Speedometer read correctly at all speeds comparing to scanner VSS speed and GPS MPH app. I suppose this is one way to do it. Could be pure luck also. Anyway, Thank you for the video and the help.
Nice video. But I suspect poor connections either at the main connection to the panel or at the plug-in to the circuit board. Crap connectors! Servicing it reset both of those, scraping the oxides off, and might have worked w/o the motor change. By the way, the motors are just a magnet attached to the needle shaft, set inside two coils of wire set at right angles; the circuit drives them with different currents to point the needles. You can measure resistance of the coils to test them and/or drive the needles to a known position by running current through a diagonal set of terminals from maybe 3V DC. Mark that and you can replace the needles to that position. Also, if you have sticking gauges, check that the needle's hubs are NOT dragging against the mask as they can easily do if pushed on too far. That made me crazy for years.
Thanks. But no, not a chance of electrical connectivity at issue here. The aircore motor is an analog device, being utilized to present a digital signal. To account for the mismatch, GM engineers specified the aircore motors calibration to also include a _dampening fluid_ to delay the needle response. This accounts for representing a digital square wave signal, until it dries out. The _fluttering_ is 100% due to loss of this dampening effect, which leaves the needle to portray the 1s and 0s of the digital square wave incorrectly in a naked un-dampened fashion.
Some folks have tried manually re-injecting a silicone fluid in to replace the OEM dampening fluid, but this is at best a temporary mitigation. It _always_ returns. Replacing with an NOS aircore motor, or a professionally rebuilt one by a speedometer repair facility, is the only viable long term repair.
There are a few ebayers and shops that lubricate and/or rebuild these motors... I just sent a P motor to a rebuilder with an excellent rating. Let's see what happens. If it comes out well I will recommend them here. My cluster is from an 05 Chevy Astro.
I hope that I can find these motors, going to replace the factory radio while I have the bezel off , it still has the factory AM/FM Delco radio.. Any help locating these motors would be a help.
Supply from China has dried up. Pinned comment has the only source, an eBay seller, left who has some stock and original equipment to refurbish used motors as well.
Fantastic buddy thanks for your help
From your commentary above: "If your gauge was very messed up you may be in the rare situation of not being able to perform the calibration procedure outlined in the video, in that situation you will have to get access to a new fuel tank sender, hook it up and use it to calibrate the empty, 1/2, and full positions accurately." My question is: If I get ahold of a new fuel tank sender in order to calibrate my gauge, how do I go about hooking it up? After installing my new aircore motor, I filled my tank, then set the needle to "Full". I've driven well over 100 miles, and the needle hasn't budged. I suspect that my fuel tank sending unit is probably bad, but I'd like to be able to confirm it.
You mentioned filling the tank, and then setting the needle to point to F. I presume you first set the needle where it was with the old aircore motor as shown in my video first. The vast majority of the time that should be enough. If you did and it was still off significantly, then yeah this additional calibration approach mentioned may be needed. But to do this accurately, you would have to have known how many total gallons used to set you at "F", or 1/2, in the past so you can drain the tank and add back checking E, 1/2, and finally F. What drives the aircore motor, and thus the fuel gauge needle, is a resistance reading coming in from the sender itself, this is within the wiring harness you connect to the sender unit (diesel) or fuel pump assy (gasoline). With a service manual, you might check that you're even getting that sender resistance value, and that the value is correctly changing with the fuel level in the tank. In fact a speedo shop would likely re-calibrate the E, 1/2, and F gauge readings after installing a new aircore motor solely on the bench from the resistance values for that particular model year.
@@DrShock I actually just today received a used instrument cluster that I got on eBay. I swapped it out an hour or so ago, and the needle went right to "Full", just like it does on the original cluster. Before I replaced the aircore motor, after doing its dancing, the old aircore's needle would settle on "Full", which is why I filled the tank and set the needle back on "Full". That's why I believe that the sending unit is bad.
Excelent video and explanation. Could you give me some advice to check why the PRNDL lights indicador doesn´t work. Thanks
On these years PRNDL part of the instrument cluster is fed range input by the park/neutral position transmission switch. I've not encountered this sort of issue before on the 90s trucks, but I would hazard a guess it could be a problem within that specific switch, or a problem getting voltage to the PRNDL circuitry of the cluster. You would have to get the service manual schematic and check each of the 4 switch outputs are making it to the IP cluster connector, then check that the lines for PRNDL voltage/dimming are making it. If those are good, it's a problem on the IP cluster circuit board itself.
It probably your neutral safety switch located on the trans mission
These are the same air cores that were used in 99-02 gmt800's, the gmt800's didn't use resistors, but all gmt400's used resistors. And the old air cores are fine and do not need replacement, they need fresh dampening fluid put in them. Your fuel gauge jumps like that because your sender in the tank has bad spots in the reostat and the dampening fluid in your fuel gauge air core has gone bad allowing it to rapidly respond to any changes in the sender signal. You don't notice it with the new air core because it has fresh dampening fluid in it to slow the gauges movement covering up any fuel sloshing or slight irregularities in the sender signal. You could have accomplished the same thing with some 30k weight rc silicone diff fluid and a syringe.
That's partially correct, I explained some of the theory around this in the video description. The dampening fluid is used because of the waveform shape used on the PCM output for these years. Only a diesel engine has a direct sender to gauge circuit though. Unless you have the appropriate shop tooling that a cluster rebuild center would have, any attempt to syringe in fluid would be temporary at best. So replacement of the aircore motor is the only long term repair. Unfortunately that supply has been exhausted. Fortunately, you can have the aircore motors rebuilt still, the pinned comment lists a known cluster shop I've done business with who has the right equipment to rebuild them which would be as good as a new motor replacement.
@@DrShock My repaired clusters I've done for people, including my own, are all still going years later after I redampened them. And only 98+ gas engines ran the fuel gauge through the pcm(97 V6's used a fuel gauge module), all 97 and older V8's, 96- V6, and all diesels(unless it had dual tanks) ran the sender direct to the fuel gauge. All oil senders go direct to the gauge.
@the section about the bulbs , these are all 194's? I assume these are clear bulbs wondering if I decided to use maybe blue if it would affect the orange needles..
No, not all of these are 194s. Some are different, see 6:53
Man I’m glad I found this video!! I have the same problem on a 1999 suburban!! I’m going to order parts to get her fixed
Did it fix your issue
So I have a 97. 5.7. Obs; the old thermostat would keep the truck running cool around 145. The temperature gauge in the cluster read that temperature accurate. However, when I put in a new thermostat. That brings the truck operating temperature. Once it hits 150 it just keeps going all the way to 240. I’m gonna check all my grounds.
Thank you I enjoy the video very much I totally appreciate what you've done.
Great video
awesome ....information now I can order my voltmeter air core n c if it will fix my discharging problem
I cant find it with the letter F for the fuel they start with the letter C for the fuel. I have a 1994 chevy blazer k1500, and excellent video by the way.
Yeah it seems the Chinese suppliers of the "F" type motors are either backordered or the supply has ran out affecting what's available on eBay currently. Personally I'm waiting a bit longer to see if the "F" type comes back in stock with the larger eBay sellers because "C" certainly isn't the original calibration. But if "F" is gone for good, "C" might have to be the next best substitute going forward. These trucks are coming up on 30 years soon so not that surprising parts availability wise.
Seems they are back in stock now as of this evening.
A speedometer shop on eBay is now selling these again, but he's only got the "C", "P" "S", and "T" calibrations currently. I put a link in the description.
I have a bouncing fuel gauge that I assume has to do with a broken slosh baffle in the tank. I haven't checked to confirm but now I'm wondering if it's the same cause as this one.
Where can you find these at I am not finding them
98 k1500 . 5.7l gas. My top two gauges have a slight twitch in unison. Assuming they share a common connection, that’s the culprit.
great vedeo mate you save me a lot money great explain!! cheers from norway
Great job Dr Shock!
Very well done video it was extremely helpful
Dr. Shock como siempre muy buenos vídeos tutoriales, específicos y educativos.
Quería hacerle una pregunta muy específica al tema:
Resulta ser que hace unos días desarme el panel de instrumentos de mi tablero del coche.
Para remplazar unos Light bulb fui muy cuidadoso aproveche para limpiar instrument cluster connector tanto en macho como la hembra con un cotton tip y alcohol isopropílico (ya que veían con algo sucios y con polvo).
Antes de volver a montar instrument cluster;
Después hice mis pruebas abrí la llave ignición todas sus luces bien, gauges bien, selector de cambios prnd123 bien.
Y al cerrar la llave de encendido.
Probar la iluminación, encendido los tail light Hooo! Sorpresa 😭.
El gauges del oil y fuel se mueven a la posición cero más que nada el del oil y si enciendo el motor y Luego tail light veo como el medidor se mueve una un poco hacia cero o empty pero como la señal del ops o fuel sender unit son más fuertes pues no se va a 0 psi.
Buscando información en internet me topé con tu vídeo ruclips.net/video/dw9Hia55yys/видео.html.
El cual me ayudó mucho vi instrument cluster connector en esos diagramas pude identificar cada pin (porcierto que libro usas, ya que aquí en México no es fácil encontrar esa información)
Me topé que el pin 29 es el de las iluminación dimming del señal tail light y hay 2 ground el pin4 que es para la electrónica del cluster y el pin 31 que es para bulb light y Gnd de los gauges veo que se comparten.
Use mi multímetro para medir resistencia y noto que midiendo el pin 4 a cualquier metal expuesto e la carrocería hay una resistencia de 20 ohms yo deduzco que a de ser la vejez de cable pues 22años.
Pero yo le pregunto sabe usted si el Gnd del cluster tiene alguna resistencia de paso como protección.
O va directamente al chassis y si para estos cluster es despreciable eso 20ohms en el conductor o recomienda reemplazarlo el cable para bajarlo a menos
Mucha información aquí, intentaré abordar la que tienes.
- Debe tener cuidado con los solventes en una placa de circuito impreso de mylar flexible como la que se usa en el grupo de instrumentos. Puede dañar el plástico en algunas formulaciones.
- Sí, las bombillas de repuesto de la marca del mercado de accesorios pueden tener problemas para hacer contacto con la placa de circuito impreso flexible. Puede levantar, ligeramente, las clavijas de contacto de los portalámparas con cierre giratorio.
- Estoy usando el manual de servicio de camiones GM genuino de 1998, que ha estado agotado durante más de una década.
- No estoy familiarizado con todos los circuitos de tierra involucrados en el esquema del grupo de instrumentos. Pero suena como un problema de fondo que está describiendo allí.
A lot of info here, I’ll try and address what you have.
- You have to be careful with solvents on a flexible mylar printed circuit board like that used on the instrument cluster. It can damage the plastic in some formulations.
- Yes, aftermarket brand replacement bulbs can have trouble making contact on the flexible printed circuit board. You can pry up, slightly, the contact pins on the twist lock bulb holders.
- I’m using the genuine GM truck service manual for 1998, which has been out of print for over a decade now.
- I’m not familiar with all of the ground circuits involved in the instrument cluster schematic. But it does sound like a ground problem you are describing there.
@@DrShock muchas gracias Dr. Shock , no sabe cómo.
El manual de reparación de la GM que tiene se le puede comparar con libro CHILTON 28624, o nada que ver el original siempre será más completo???
Para concluir podría hacerme un favor :
en su otro vídeo muestra en su manual GM en la hoja del :
"instrument cluster connector"
Que el pin 4 y 31 que comparten Gnd menciona que revise el circuito N° 451 de su libro.
Agradecería si me mencionara si el cable va directo y atornillado alguna parte metálica carrocería o chasis y porque área aproximadamente se puede encontrar esa conexión en la cabina o si pasa por algún circuito de protección y por eso la pequeña resistencia.
Dr. Shock de lo demás yo me encargaría e investigaría.
De antemano gracias.
He utilizado guías de Chilton para vehículos en los que no tengo el manual de GM a mano. Ciertamente son buenos libros y los recomendaría. Pero no puedo decir si la camioneta de este año tiene lo que está buscando esquemáticamente.
No he tenido que depurar el circuito de tierra del grupo de instrumentos, así que no puedo decirlo. Pero conecte a tierra cualquier circuito de tierra 4xx (por ejemplo, 451) que se ubicará en el área de la caja de la rueda trasera / cama.
I have used Chilton guides for vehicles where I don’t have the GM manual handy. They are certainly good books and I would recommend them. But I can’t say whether the one for this year truck has what you’re looking for schematic wise.
I haven’t had to debug the instrument cluster ground circuit, so couldn’t say. But ground any 4xx ground circuit (e.g., 451) is going to be located in the rear wheel house/bed area.
I have a 2wd Suburban with barn doors and no fog lights, but all those plugs are there behind the cluster bezel. I guess they used one harness for all their trucks.
Great video! I changed the motor with a new one. Included the resistor and the motor is making a buzzing sound. I replaced the sending unit and fuel pump and still the same issue. I even tried a used stepper (F) motor from a different dash. Guys - I’d appreciate any thoughts on where to go next. Thanks!
Is the buzzing only coming from the aircore motor for the fuel gauge? Did the old one make this buzzing sound as well?
Yes, the buzzing is only from the air core motors. I’ve tried three of them.
To clarify…only from the fuel gauge air core motors.
And even the original motor was buzzing? If not, was the motivation to replace it due to the needle dance problem alone? My first reaction with this symptom is a wiring problem heading into the cluster, but the original aircore motor should have exhibited the same noise.
The original motor had a very faint buzz to it but almost inaudible. I placed my finger on the stem and could feel it vibrating. The new motor was more amplified and also vibrating.
The idea was to correct the vibrating fuel gauge and fix the random intermittent fuel reading. Most of the time it would read correct and then randomly show empty or a full tank and stay there for some time. Thank you for your questions and trying to help.
I’ll get under the truck and follow the wiring harness this weekend and see if I can find anything.
My gas gauge works fine,but it moves back and forth about 1/8 in when my turn signal is on. I think it has something to do with using heavy duty flashers. It never did that until I installed those.
The gauge moving while stopped, only while the turn signal is engaged certainly sounds like just a current draw issue to me as well.
Same issue..my gas gauge jumps from full to empty..I have just been making sure I keep it full at all times
At least now I know how to get to the little light bulb for the P R N D 3 2 1 indicator.
Now I know how to disable the ABS light and service 4wd light. No front half shafts or drive shaft.
Pulled the ABS fuse because I almost ran into the house because the ABS decided to wig out on me on dry pavement.
Normally the only issues with abs on these trucks is the front hub sensors. The hub rusts and the sensor is a magnet. So it flakes off and sticks to the sensor. If there seized in there just buy new ones if not pull them out clean off the crap and plug your fuse back in.
Enjoyed this video. Have you thought about going digital instead of analog? Had the same issue with my vehicle then decided to replace the gauges with digital.
Nah, I prefer the OEM analog look myself.
where did you purchase the stepper motor from
These years don't use stepper motors, they use analog aircore motors. Check the description for some links.
Both the fuel gauge and water temperature Guage in my motorhome are stuck. I'm going to use your techniques to fix them. RV mechanics charge huge fees for repairs.
One indication it's a grounding issue is when two or more gauges dance similarly.
For the last year or so, my old 1993 C1500 was exhibiting the issue. I pulled the gauge cluster and cleaned all the electrical trace push-in electrical connections. I installed brand new lighting bulbs too!
The problem didn't disappear. Eventually, I started having symptoms of the engine and transmission dropping out for moments. Then, the engine really started cutting out and bucking.
Okay, I guess I gotta do something real about the issue now...
Powers and grounds, it's always powers and grounds.
In the engine bay right behind the alternator, there are two studs about 4" apart. Each stud grounds two wires. The terminating lug at each connection was a green creepy crusty mess. I cut the wires back a bit, soldered in new wire lengths, soldered in a new grounding lug, heat shrink tubing everything, cleaned up the stud mating surfaces with a wire brush cup on a Dremel, and reassembled everything.
The gauge jitter mostly disappeared and the 5.7l V8 is back to its sewing machine smoothness.
One issue remains, however, The volt meter drops from a reading of 14 to 10 and back to 14 when the turn signal flasher is operating. So, should we get a comfortable day temperature and dryness wise, I'm going to refresh the grounding terminations for the front and rear turn signal circuits.
Powers and grounds, it's always the first thing to verify and check!
You could start here on the grounds, ruclips.net/video/H0lK0TZEVCc/видео.html
What's shown in this aircore motor video isn't ground related behavior, but it is a good checklist item to start with.
Thank you! Very very helpful
Good man. Thanks for the info
237K, Still going! I have 288k on mine, still going great