Cooling Fan Stuck-On Case Study: '04 Toyota Highlander
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- Опубликовано: 27 окт 2015
- The cooling fan on this Toyota stays stuck ON when the car is shut down, draining the battery. Once again the trusty test light saves the day and leads us to one of the most bizarre wiring issues I have come across...
I can say for certain, that no amount of parts-swapping would have fixed this car!!
Enjoy!
This is another great example of how a wiring diagram and a test light "scope-on-a-rope" can pinpoint very obscure problems. A fitting title for this vid could be "Advanced test-light diagnostics".
For a more thorough breakdown of this fan control circuit, check out ScannerDanner's vid:
• Video
I apologize for the poor lighting and shaky camera at the end...it was late, I had a cold, and had to finish up the repair :)
Enjoy! 
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Very few people out there that are determined to fix a problem like this and then to share it, gives me hope that there are still some honest hard working mechanics. Cudos to you.
Thanks Raymond! This was a neat case study :)
A 20 year master tech just want to thank you, have the exact same issue you saved me time and the customer money, I have never seen a short through the connector bit sure enough that was the issue, I had the junction box all apart and still couldn’t find the issue, thank you so much for sharing!!!!!!!!
That's awesome! One of the weirdest electrical failures I have ever seen on any car! 😅
Well, I still have a 2004 Highlander and it did exactly what was described in this video. Once I pulled the blue/white wire, the fan stopped running. I went through all the checks that was described here and was amazed that my problem was exactly the same as described. I would never have found the problem without this video. Good job tracing this electrical anomaly.
Wild, I just watched Eric O have almost the same problem on the same connector on a Toyota! His were all crusted together. He had to completely take the connector out of the wiring. Good investigative work Ivan! Tom
great detective work Ivan. you and Eric.O have taught me to never give up on a repair. I'm an appliance tech for a very lage company for 27 years. going out of the box to watch you both in another industry is amazing. Different field, but same work ethic and diagnosing procedures. I thank you and Eric.
+Randy Gudeahn (ProTech) Hey Randy you are absolutely right about the diagnostic procedures and thought process being very similar. Most modern appliances are all logic-controlled and programmable just like cars!
I had to troubleshoot our house heat pump a few years ago. It was throwing trouble codes (!) for the outside air temp circuit...turned out to be a bad thermistor. Can't imagine how expensive a diagnostic/repair house call would have been on that thing!
Who in their wildest dreams would have thought those two wires were shorted together inside the connector. Great work Ivan with the diagnostics!
+stuzman52 I couldn't believe it either, Terry! Thought my Ammeter was lying lol
He fake it. Its the youtube "McGuffin", a "McGuffin" is the excuse to make the plot swing, don't matter if its true or false. Show biz 101.
@@felixcat4346 stfu dumbass
BBB you broke my heart..... No more wiring diagrams -- I wish I could find another site, but so far no dice.
Intelligence + determination = win. Great work Ivan.
Awesome video..mechanic myself all my life, 25years, and consider myself very adept with electrical problems like these. Great methodical thought process and great use of following wiring diagrams and using testing equipment..enjoyed watching
I thought that you had lost your mind when checked amperage on the dead end of that connector . VERY GOOD JOB !!!!!!!!!!
Thank you ! , I just encountered the same issue with an almost identical vehicle.Your diagnostic work saved me hours , furthermore the problem could have led to some other expensive potential solutions as there was absolutely no evidence of a problem with the connector on my vehicle . Nice work & thanks again!
Ivan. IMHO, superb troubleshooting! You and Eric O are killing me! I never knew just how much I did not know about troubleshooting cars - I'm learning, thanks to you and Eric O. Many thanks for the "Heads up" with BBB Industries - now a member of their data base. Many, many thanks.
Great walk through system design and operation Ivan. Thanks for sharing.
Love that you take us all the way Amigo. I'll keep watching sir
Ivan, that was excellent!! The three things that really helped me in this video were 1. Your use of the incandescent test light. 2. The ammeter clamp on probe. 3. Your skills at interpreting the signs. Also appreciate your BBB comment in answer to a fellow subscriber. Class was very good today!!!
He did good job for tracking the problem ! very clear explanation !
My Toyota has the same exact wires and issues you did! So weird!! Thanks for the video wouldn’t have found it without your video!
Pretty awesome diagnostics, dont stop doing this
Great job Ivan. The test light is always a valuable tool.
Same issue and your video was a great time saver. Excellent diagnostics process!!
Mike in Canada
Just did a customer's car with the exact same problem. This was extremely helpful. Thank you.
Hey there! I currently have the same problem. Did it end up being in the connector pointed out in this video/was it fixable? Praying it is bc I just put in a new battery and alternator just to find it still has a parasitic draw. Thanks in advance
Nice clear analysis and resolution. Impressive. Well done.
Holy moly dude!
Just finished up my mom's Highlander. It was literally this exact same issue! Even the pin broke off as well!
Thanks so much for posting this, honestly not sure I would have gotten it myself.
NICE! I thought no one would ever find the same problem as here. Good thing you didn't take it to a shop and watched RUclips instead ;) P.S. If I helped you save a bunch of money feel free to click on the Fan Funding button too. Glad I could help!
thanks Ivan that was a brilliant case study, I learned a lot about electrical trouble shooting and using the ammeter, hope u charged plenty and remember there is always the cash in the fuse cover! cheers sandy
Pa awwaaaay was
Eric O had the same connector go on one of his repairs. This time it went up in smoke and had symptoms of alternator and abs issues. It took out 2 fuses, a 7.5A and 10 Amp both wires were next to each other in the connector. Full rewire of connector cured all faults
Wow, nice investigation on this, very impressive detective work. Really impressed with you drilling into the schematic. Could be my problem as well.
Thanks for the great vid. I started out with the same cooling fan problem. Later in the day my car started stalling at idle. Instrument panel was going crazy. Trans would skip when I turned on ac. I had one of the pins in the same connector come off when I opened it up. I ended up bypassing the connector with 4 sets of wires over a couple days and everything is great now! Thanks so much for the thorough diagnosis and education in electrical troubleshooting. Great wiring diagrams and info at website you mentioned. Way better than Haynes manual. Thanks again.
That makes my day! Great job on the repair, hopefully your Toyota will be problem-free for a long time :)
Before the fan ran continuously, I also had idle issues and transmission skipping issues, just like what you are describing. How hard would it be to just replace it with another 10 pin connector? I'm tempted to just bypass the two wires like Ivan did, but now I'm wondering if other pins are going to fail and cause assorted malfunctions. Bad design.
dude! thank you my shop was chasing this problem for a week this ended up being the problem... super helpful
Cool! Hopefully the methods shown here will cut down the diag time from weeks to hours on the next one 😁👌
Great video , good diagnosis skills ! Testlights are awesome !!!
Another excellent video , that amp probe is a must have in automotive today .
Ivan, you are great mechanic. keep up the good work
That was a crazy diagnosis. Who would have thought shorted wires in connector. I bet most shops would have thrown relays and a computer at it. Awesome job!!!
+buzzerauto Yup that situation could have gotten ugly with parts swapping...good thing they stopped at just one relay!! Hopefully the computer driver for the fan relays survived the short. Maybe should have bi-directionally checked it?
+motoYam82 Maybe but I sure there fine. I guess you should always verify repair. I've had connector issues on stuff but I usually find green corrosion or damaged connector. But this video shows that there doesnt have to be anything visual to be a problem.
Awesome 👏 work helps me learn more about diagnostic troubleshooting
1, 2, freaking barbecue! Quick and dirty repair. great job
Wow never seen that before! Nice diagnosis! But I'm gonna go take some dramamine now
This is so helpful i have an issue with corolla ae101 very similar. Will now look into connectors on the bottom of the fuse box and check on the pins.
The 'wiggle jiggle' test is legit. Nice video!!
WOW! that was amazing diagnostic.
Thanks man, I have a similar issue in my Toyota Camry. Gotta use your technique
Good find , Who would of ever thought
That was cool! Awesome video Ivan!!
Another job well done. Congrats.
Thank you that was really helpful I have this problem today. Hoping I will fix it tomorrow.
Ivan, very well done deducing the possible causes of the short ! Is it drawing current and how much ? Now that is what a Amp Probe is suppose to be used for! excellent diagnostic skill !
Had the same issue with my 2007. Luckily it turned out to be a relay stuck closed. Thank you for the video!!!!! I wouldn't been able to figure it out with out it
Good to hear Roger! Feel free to donate a few bucks via the PayPal link; it helps to fund the information services like wiring diagrams that I share in the videos 🙂 Thank you!
Thanks!!! This saved me so much time.
Great example of logical testing Ivan.
this is an old video, but I just had the exact same problem 2 days ago. Helped me a bunch to find the fix. THANKS!
whats the issue and how you fixed it? thanks.
@@Yonipzz The wires to the fan/switch right at the plug from the main harness were burnt. Just repaired the plug.
@@joachimbartsch1045 thank you for a quick response.
Nice, don't see that often. I've never seen it inside the connector . 👍👍
Hi Ivan, watched all of your videos and i have to say have come a long way with your diagnostic capabilities. You even convinced me i need to buy a stand alone amp clamp so i don't have to take out the scope every time. Good job with this :)
Sounds like you're fighting allergy or a cold. Stay strong!
Thank you. Just had this exact issue pop up on my 05 Highlander and jumped right on RUclips to investigate. I JSU put $2k into repairs on both my vehicles and didn’t need this. I went right to the plug you identified and could here the relay tripping and arcing when I wiggled the connector. Then it got hot and saw a puff of smoke. Pulled the battery, opened the plug and found the pin pretty much melted. I hope jumping around the connector is the solution. I’ll let you know.
Well, did it work or catch fire?
that was a good one! Thanks for showing us
Hi, thank you so much the video, it was very informative. I have a 2008 Lexus RX400 H. Both radiator fans and heater blower fan continue to run with engine off and keg out. When turn on with they are off. I did all the tests you have shown in the video. Tested the load side and it has 12V and side the going to fan and feed 12v to side and unplugged the fan and everything is just good. The problem is control side has 12V with engine off and key out when I remove the heat fuse it off. I also check the negative side of the control side of the coil and it going fine ( in your case you 12v) I don’t have the wiring diagram for it, can you please help me find what is feed the control with key out. Thanks
Educational as always
Amazing how you chased that down...
Amazing.. lot of information
Thanks man ⭐️💕
when you did the repair you mentioned you spliced the two wires, bypassed the one wire 27:12. I am confused so my question is which wire were you speaking of according to the diagram that was bypassed and what did you splice it to? thanks
+Ozzstar Ended up bypassing the connector with BOTH wires that were shorted together. The pin for that white/blue wire (not on the diagram...not sure where that went) was actually very weak inside the connector due to corrosion, so had to bypass that one as well as our red/yellow PCM control wire for the fan relays :)
Okay gotcha now, you bypassed those two wires from the connector. You connected the matching wires (butt connection), outside of both connectors. Nice fix man, great diagnostics
What wire did you bypass the red/yellow on to? The left side (female) plug has no red/yellow wire coming out of it.
I have an 03 highlander 3.0 v-6 and the fans won't come on at all. Even when turning the ac on, nothing. Both of the fans work when given 12volts.
All the fuses are good inside and out.
Replaced the relays with new and that didn't work either.
Temperature reads normal but its winter. Its not overheating, yet.
I'm looking into replacing the fan switch but would that cause them not to come on even with the ac active?
I have the exact same issue going on with my Solara. How does one go about fixing those wires? This car is pissing me off, I mean I can't walk away from it without pulling the two fan fuses.
Wow, I’m having this exact problem in an 05. Amazing work thankyou.
Yeah it's a weird problem lol
@@PineHollowAutoDiagnostics somehow the voltage reg got cooked when jiggling wires.,,
Exactly my symptoms up to and including isolating the ECM. Great video in any case I never would have got this far otherwise or understood as much about how the circuit functions. Trying to figure out how to unplug the connectors and remove the relays is not an easy task. I found when trying isolate the ECM that the plug wires on the male side of the plug were hot to the touch. And there was contamination inside male plug half around the pins. 2005 Highlander. I hope this is the answer... and cleaning the plug I found a loose pin that was corroded and easily fell over and broke...final and, I soldered in a bypass wire and now the fans, fan when they are supposed to and all the warning lights are gone.
Was it the answer? I'm about to do the same on my '05 for the exact issue.
@@jimyaekel7385 yes it was "an" answer and did remove most of my symptoms. I don't profess to understand all I did. But simple observation of the state of the pins in the connector said those were a likely starting point. I made sure I understood and and documented the pin out and the wire colors before I started. I found some crimp splices that worked well and sealed with heat gun.
kenbig1 as an electronics technician I think you did a very methodical troubleshooting job. When my connector started getting hot and even smoking from manipulating it, that was a pretty obvious sign. But on mine the pin actually cooled off and the green/ yellow wire alongside it showed signs of overheating also. For good measure I bypassed both of those and the red one you did. I solder wires, just wish I’d had some shrink tubing. I’ll have to go back to it. But the fan running issue is eliminated and no more relays clicked and arcing. Thanks for your post!
how did you bypass the wire? did you solder the one wire directly to the corresponding with on the female side of the plug?
good work,ivan
Far out, far out... well done, well done!
Wow, nice find.
Unbelievable ......thanks Ivan....
I would put some sort of connector on that wire in case if it needs to be unplugged.
Great video.
Ivan you are a superhero
Good job Ivan
excellent video ivan thanks
Ivan, I got 2005 Highlander with a intermittent P0012 code and the VVT solenoid checks good but I want to check the filter. I can't figure out where it is located. Does anyone know where it is located?
great vids! keep em coming
Charlie Hinna
Very Good job well done. You are the best
Thanks for wonderful video. My Highlander radiator fans run on low speed,but when i switch on A/C ,it runs on high speed. This has make me to change the radiator bu the fan run on low speed. What could be the problem? My Highlander is 2004 model.
I touched my 2008 FJ cruiser headlight plug when installing my xenon hid..
Now there is no low beam, I am preparing to do same thing you do here.
FJ cruiser DRL with headlights system makes things very difficult,
God help me
I even bought Fluke117 for this. Do I need lights tester!
awesome video awesome job thanks man
Hey thanks man this was life saver. Had this happen on 1 i had after a sunroof drain clogged so i was looking inside and cleaning connectors. Found this and could hear the connector sizzle while unplugged. I ended up also having a battery light on because the wire it shorted to lost connection after i repaired the other.
Nice work! Crazy that a connector can short out internally like that 😅
@@PineHollowAutoDiagnostics yeppers, i cleaned it and it was good but i couldn't leave it,i knew it happen again so i just bypassed it like you
Nice video! Toyota fan control is strange. Same set up on the rav-4 as well! They do have to break sometimes or I'd go hungry!
+Toyota Tech lol I thought you would chime in on this one!
Fixed my issue also. Thanks
Hi Ivan, where can I buy that test light you have? I need an old school incandescent trouble light like that... thank you and amazing diagnostics!
Harbor Freight! Or Online...search for ATD 5513 :)
Superb piece of fault finding Ivan, DC ammeters are a lot cheaper nowadays an excellent fault finding tool, pick cheap ones up for around £30, but if you can afford the top notch ones then carry on. What's the odds on a local garage finding that one then ?, keep up the excellent videos.
+DiyMech Thanks! Yeah the more I use the amp clamp, the more I like it...great non-intrusive tool with no leads to plug in or get in the way. In this case it was the most effective way to pinpoint the problem without cutting wires or poking holes. It's a fantastic piece of equipment when paired with a test light :)
my 05 highlander has a peculiar issue. when the AC kicks in the cooling fans i get a red battery warning light. voltage is 13.4v red light on. oddly, i can turn off the AC and put a massive draw on the system with heated seats, lights, rear defrost, blower motor..even wipers and power windows...it drags the voltage down to 12.5 but no battery light.. only get battery warning when the fans kick on so its not directly related to low voltage/failing alternator ( Not belt slip..if i wait for engine to heat up and fans to kick on for cooling it does the same thing so not specific to a/c use)
Well done a real head scratcher.
Were u get the diagram?
Hi please advice I've got 2012 peugeot 3008 1.6 A/T vti petrol my fan allowys on while driving sense starting the engine and when I switched the engine off the fan stay for 5 on then it's off and the battery many times died please help and the car taking so much petrol, thank you
the EB2 connector is my guess second connector under thr front of the relay box. either melted of water intrution and corrosion.
Holy crap, batman! My '04 Toyota Highlander is doing this exact thing. I never imagined that this would be such an involved diagnosis. I mean, when do plugs go bad? And how many mechanics would find something like this? Thanks.
Great diag on this.
Literally just had this issue today! I followed this video to the t and my test light showed the exact same symptoms. Thank you so much for posting this so I didn't have to take it to the dealer and have them chase this gremlin.
Wow same exact short in that connector?! I would never have guessed that anyone would see this problem, as it was so bizarre!
When we unplugged the ECM and wiggled the connector and the test light started flickering I almost lost it haha
What do you mean by bypassing the two wires?
BBB no longer offers TSBs and wiring diagrams. We apologize for the inconvenience.
Good old test light and ammeter. Feels good solving problems like that..
How do you check relay? What if the relay was bad?
The Toyo cooling fan circuit is a nightmare. The ECU does not control the under hood fans. They are controlled by the ac water temp switch and the ac pressure sensor.
Never seen a short in a connector. I have seen open circuit connectors caused by
improper backprobing. Good job! I would have given up.
I have a Peugeot 308, the fan keeps running as soon as I start the car in the morning, so the engine isn't hot at all. I've replaced the thermostat sensor & the problem is still there. Could you please assist me with my problem as I feel the garage is trying to rip me off. Look forward to you're reply.
Thanks
Jas
Get a wiring diagram and see what controls the fan relay 👍
IVAN YOU SOUND MORE LIKE UNCLE ERIC EVERYDAY.
Oh man, how long did you take? I’m going to bring my car for service 180 an hour to figure out. Hope it didn’t take as long as it did with you. My fan comes on when I turn on my high beans when I shut off my high beans, the fan shut off truck has to be off so weird
Figure it out yourself! 😎
How can i get that wiring diagram
how long did this take to find out in real time not camera time. very interesting find
+phil holbrook hmmm about two hours with the repair and filming...
crazy I'm working on the same vehicle which is a 2005 highlander 3.3 ... that wire which is was hot all time mines is that is doesn't have no voltage nor ground wire is dry ...fan do not kick at all unless i give direct power will run... i need some help!!.. but this video has help a lot this is amazing
Hey man i can help you with your problem if yiu would like