This highlights the difference in a backyard mechanic and a professional technician. You do not test for continuity of live circuits, with the fuse still installed you can get a false positive for continuity by detecting reverse through a complete circuit and the fuse is actually blown. You can pull the fuses and check for continuity, or most easily you can start the vehicle and turn on all the accessories then check for DC volts between chassis ground and both sides of the fuse.
@@Ha-42 No, because it's not just about having power available to the circuits. It's that the circuit can loop back around and give you a false positive. It's best to remove the fuse when using the continuity feature of a multimeter to check if a fuse is good. To check fuses without removing them, it's best to use a test light or DC voltage feature on multimeter. If test light lights on both sides of fuse, then fuse is good. If test light lights on only one side, then fuse is bad. If test light doesn't light on either side, then that tells you there's no power to the circuit and you need to turn it on to check it.
@@bernardocisneros4402 Unless the rest of the circuit is functionally just a closed loop of wire, that probably won't be an issue. The real issue here is an incomplete understanding of circuits and continuity. Taking the fuse out reduced the circuit to the fuse, your probes, and the multimeter, which is ideal.
@@jnharton You're right but it's much quicker with a test light and the vast majority of fuses are going to pass with a test light. The ones that don't pass, I remove and check visually and with ohmmeter.
Wrong!!! Set meter to voltage - test across fuse If you read voltage (12v) fuse is bad. NEVER test across a fuse in place with continuity or ohms. If you do that with highr voltage (house hold 120 / 208 ) you will fry your meter. Fuses should only be tested with continuity when removed from the circut.
@thehomicidalduck6867 It depends on voltage of circut being tested. Automotive is 12 volt. House is 120 / 240. Industrial 277 / 480.. You have proven a little bit of knowledge is dangerous. You should not be making videos like this, knowing so little. Be safe. Shut off power. Remove fuse then use your ohm meter
Thats why on a lot of equipment that I work on and on our personal vehicle I changed all the fuses to the ones that light up to let me know they are popped, sometimes they wont light up so i dont fully trust it but its easier on my back lol not having to lay back down like I was able to back then lol.
My friends 2012 focus has a completely dead stereo and some other electrical flood damage. I did this to check all the fuses. Unfortunately we weren't so lucky for it to end up just being a fuse. Still have to pull the head unit.
@@HoodRichSWERVE well I pulled codes looking to make sure the other o2 sensor didn't go out. but it's a p0420, turns out the catalytic converter has a chunk missing out of it. pieces bouncing around in the muffler. anyway, there were a bunch of u2100 (I think) codes that all pointed to the clock spring being the culprit. as I later found out the cruise control doesn't work either. so now I have to pull the steering wheel apart and check resistance across the clock spring... not something I want to do if it turns out to not be the problem.
Excuse me, basic electronics here. You don't test using ohms setting on an energized circuit. You check for voltage, across an open fuse you will read the applied voltage or 12v here.
yep. thankfully newer (and good) meters have safety built into them to prevent damage to the meters, or at least that's what i've heard. but, going back to basics, this is def not how u do it... unless u disconnect the battery, which is another context missing in this video
Not correct I’m afraid. Don’t check for continuity on live circuits. You should set the meter to V DC, connect -ve lead to chassis and then use +ve lead to check for the same voltage on both sides of the fuse.
Yes it will. This is called continuety test. You can also test electrical cables just make sure they are not plugged in the 110v ac or 220. You can also test the switching sides on relays , you can also test other switches as well. Multimeter is to me a must have. Makes life so much easier and prevents one from making costly mistakes.
How do you know a nox sensor is bad if its not leaving faults code we keep seeing cars with hi nox faults but not exactly saying whats wrong is there an off car test that can be done
This in theory could damage a cheaper meter, unless you disconnect the battery first. With a fuse blown you could have 12V and high current available. Not a problem testing good fuses as there is no potential difference across a good fuse. Just be aware of a possible issue with blown fuses and the battery still connected.
I have been doing this with cheap meters and bit more expensive. Never had an issue . Working on 12v and 24v vehicles now for 18 years. Many times tested fuses like this. And got a few that was blown that you could see there is defently a short circuit.
@frikkiesmit327 why not measure the voltage on either side of the fuse? Or even measure a voltage across the fuse? You won't subject your meter to voltage on the resistance range that way. Any good meter today won't care, but old digital meters and analog meters could be damaged by subjecting them to a voltage while on the resistance range. Trust me, it happened to me. Yes, I'm going back maybe 45 years, but think what you are applying to the meter! It's fine to check continuity across a fuse with the power removed, but in your example the power from the battery is still applied to one side of the fuse, any device that the fuse powers up will be taking the other side of that fuse to ground, probably at low impedance, meaning there will potentially be 12v across the fuse, if it's blown. Like I said, modern equipment today won't care, but older equipment could possibly be damaged. Would you measure a fuse like that on a mains powered piece of equipment while it's plugged in and powered on? Probably not !! And why not? Because of a possible damaging potential across the fuse !! It's the same principal ! If your equipment is modern, i.e., 18 years in the automotive trade, then I would not expect it to get damaged. I go back 50 years! Yes, all my Fluke,Tektronics, Bryman, and even most of the cheap Chinese equipment today won't care. But with something old, you could be taking a gamble.
I blew a tester using this method. You would think nothing would happen when testing across one wire, but if the fuse is open, you may actually subject the tester to voltage.
@@peterjohnjoseph give it a minute. . . Think. If it breaks in the middle, and you connect a lead to 1 side, through your meter, touching the other side with the other lead, both sides are now bridged. Hence, the meter will bell out for continuity.
Not as practical because power is not always running through the fuses unless the component is on whereas continuity can be tested whether the component is on or off.
A time when engineers showed love to the mechanics who would service the car. Nowadays, it seems they do everything they can do make everything a pain.
This is not the way to test fuses accurately, it is possible to get a “back feed” this way from the circuit it is connected too due to shared circuit, can lead you down a rabbit hole.
If you get a backfeed then meter will display a - on screen and OL ( overload) . I have never gotten that when testing fuses like this. Ive been working on vehicles for 18 years and did test fuses the same way as in video
@@frikkiesmit327meter will not read OL if there is back feed. If there is back feed you will get a reading. It’s best practice to always remove the fuse. Yes it’s faster to probe right across it but in the case there is some back feed like stated your going down a rabbit hole.
Then check if theres maybe some other main fuses. Check also on back if the wire that goes into port is still secure. It has happend on some cars like a polo v/ wagen which the factory through they were clever to make sure the wires going to fusebox was under tension. So that caused a wire to pull halfway out so fuse didnt even touch the terminals. Which caused the cars centre lock not to work.
And also if the terminal doesnt securely clip inside fusebox than what happens is when you insert fuse, you pushing the terminal away leadinh to bad and no connection.
Just dont use test light on any of the wiring harnasses. You can easily trigger and deploy airbags of a vehicle. It happend to one technician few years ago. Test light the old type which just consists of globe, they are basicly a short with little resistance. The other test lights with leds are safer.
You will be surprised how many people dont know this simple test procedure . And some you can show and they dont care to learn it. They rather call the one that knows 😂
It’s not about “caring to learn it” 35 plus years forklift/plant & I’ve picked up good pointers here on RUclips, I’m saying potentially a shared circuit, or someone who has bridged into the circuit further in, or a relay that has snapped internally etc etc could cause a back feed, been in that position. Also, by testing across the fuse, you can’t see the deterioration across the fuse weakest point, been in many a situation where the circuit stops, being mobile a engineer, 2/3 hours later when we turn up fuse has cooled & 2 pieces of fuse are now touching, no fault found, circuit heats up fuse opens across break, don’t have to have a blown fuse to have no circuit, not personal, but I’d rather do my due diligence, job done right, no repeat calls, have a good day.
🤔 This is incorrect. Continuity should only be checked with no power in a circuit. A (non led) test light applies a load to the circuit and is more effective than your suggestion.
Thanks man, bitch been take out each fuse then check it . I was thinking about how much time it's taking me for fuses under the hood, then under dash. Thanks man
I had some problem with a 30amp fuse, looked and acted completely normal, had power flow and everything, buy as soon as there was heavy draw I kept having issues, I replaced and isolated everything just to find the fuse was faulty and half connected 😅
@@codypalmer2732fuses breakdown/wear out but don’t blow until what you describe happens, for us mobile engineers the circuit has cooled down, fuse element touches, continuity ok, experience tells me when chasing this type of fault renew fuses.
Blown fuse, one side will be 12volts ,the other side earth via the load. Resulting in a blown fuse in the voltmeter. Better to test for voltage to ground.@@alecpajor9273
This is bull shit… one major flaw that isn’t mentioned. You MUST have the battery disconnected from the vehicle or a resistance test won’t work. But the next major flaw is that if you are checking fuses you are looking for a reason that something in the car isn’t working, right? Well, if you use this method correctly you will only know if the fuse is good or bad. You won’t know if there is power at that fuse. Just use a test light with a incandescent bulb.
Can you check fuses to see which one is draining your battery with this same method? Here is the thing. I don't know shit about electricity and eveyrhing about it confuses me. Everybody here on you tube on some different type of testing and setting on the multimeter.
NO. Read a book, use the internet, take a class or watch a lot of RUclips videos to learn about electricity and how to troubleshoot electrical problems.
thk u for not making 30 min before showing nothing like a lot of channels,you've helped so many gg.
Thanks! That’s my goal!
Amen to that bro
😂 so true
Thanks! ....I was going crazy looking for that fuse that controlled the running lights....you da man!
No problem 👍
This highlights the difference in a backyard mechanic and a professional technician. You do not test for continuity of live circuits, with the fuse still installed you can get a false positive for continuity by detecting reverse through a complete circuit and the fuse is actually blown. You can pull the fuses and check for continuity, or most easily you can start the vehicle and turn on all the accessories then check for DC volts between chassis ground and both sides of the fuse.
What is the battery is disconnected? This method would be fine then right?
@@Ha-42 No, because it's not just about having power available to the circuits. It's that the circuit can loop back around and give you a false positive. It's best to remove the fuse when using the continuity feature of a multimeter to check if a fuse is good. To check fuses without removing them, it's best to use a test light or DC voltage feature on multimeter. If test light lights on both sides of fuse, then fuse is good. If test light lights on only one side, then fuse is bad. If test light doesn't light on either side, then that tells you there's no power to the circuit and you need to turn it on to check it.
@@bernardocisneros4402 Unless the rest of the circuit is functionally just a closed loop of wire, that probably won't be an issue.
The real issue here is an incomplete understanding of circuits and continuity.
Taking the fuse out reduced the circuit to the fuse, your probes, and the multimeter, which is ideal.
@@jnharton You're right but it's much quicker with a test light and the vast majority of fuses are going to pass with a test light. The ones that don't pass, I remove and check visually and with ohmmeter.
Thank you. This was a legitimately quick and helpful video
Wrong!!!
Set meter to voltage - test across fuse
If you read voltage (12v) fuse is bad.
NEVER test across a fuse in place with continuity or ohms. If you do that with highr voltage (house hold 120 / 208 ) you will fry your meter.
Fuses should only be tested with continuity when removed from the circut.
What volt is the fuse supposed to be?
@thehomicidalduck6867 It depends on voltage of circut being tested. Automotive is 12 volt. House is 120 / 240. Industrial 277 / 480..
You have proven a little bit of knowledge is dangerous. You should not be making videos like this, knowing so little.
Be safe. Shut off power. Remove fuse then use your ohm meter
Yeah well you just freaked me out... ugh! I thought I had it. Clearly I don't!
So what he’s showing in the video he should say this can only be used in vehicle applications?
He could be testing with the battery disconnected
Thats why on a lot of equipment that I work on and on our personal vehicle I changed all the fuses to the ones that light up to let me know they are popped, sometimes they wont light up so i dont fully trust it but its easier on my back lol not having to lay back down like I was able to back then lol.
My friends 2012 focus has a completely dead stereo and some other electrical flood damage. I did this to check all the fuses. Unfortunately we weren't so lucky for it to end up just being a fuse. Still have to pull the head unit.
How did it go? Hope it all is back in order and working again!
@@HoodRichSWERVE well I pulled codes looking to make sure the other o2 sensor didn't go out. but it's a p0420, turns out the catalytic converter has a chunk missing out of it. pieces bouncing around in the muffler. anyway, there were a bunch of u2100 (I think) codes that all pointed to the clock spring being the culprit. as I later found out the cruise control doesn't work either. so now I have to pull the steering wheel apart and check resistance across the clock spring... not something I want to do if it turns out to not be the problem.
This is awesome, all these years i never even thought of this 😂😂😂 THANK YOU!!
Are some fuses not suppose to light up unless the key is in the ON position ?
Excuse me, basic electronics here. You don't test using ohms setting on an energized circuit. You check for voltage, across an open fuse you will read the applied voltage or 12v here.
Ye u can u go try it for yourself put a blwn fuse in and a good one and try both u will see
yep. thankfully newer (and good) meters have safety built into them to prevent damage to the meters, or at least that's what i've heard. but, going back to basics, this is def not how u do it... unless u disconnect the battery, which is another context missing in this video
If you test for voltage what reading would tell you if the fuse is good or not ? Im just asking idk
@@buffalo_662112v on both ends measuring from the same “zero” somewhere (ie. zero voltage drop on the fuse itself)
12 volts on either side of the fuse
thank you!
maybe a stupid question but is the car on when you do this?
This is not the right way to check fuses. Read comments above to learn how to do it the right way.
Thanks! I tought my electric mirrors went bad but I tested the fuse and indeed was burnt
I usually just use a test light. Or if im feeling spry, my power probe.
Interior fuses i use the door hinge as my ground, and just quickly touch.
Not correct I’m afraid. Don’t check for continuity on live circuits. You should set the meter to V DC, connect -ve lead to chassis and then use +ve lead to check for the same voltage on both sides of the fuse.
What if the battery is out, then this method is ok?
Short and sweet, thanks dood
THANKS BRO
Thank you. This was very helpful!
Thank you! Super quick and easy to understand.
Should the battery be disconnected?
it need power from somewhere to work lol
@@danielm94437 not for continuity
In this demonstration remove fuse to test the integrity of the fuse. The multimeter uses its own internal battery for testing continuity.
Does the car have to be on or off and do you have to disconnect the battery
Doesn't matter
What settings do I put my meter on? I just bought on from harbor freight and I need to check my fuses
@@single_dadthere’s a few ways to check
Thanks
Good Day Sir, I try to use NCV METER FOR MY CAR, and testing it. I didn't turn on the car and detect my car of live electricty. Is it safe?
Thank you bro this a one of those things I should’ve known by now 😂😂😂
Do i need not have to disconnect car battery?
Will this work if the battery is dead?
Yes
@@nicholaslombardo9696 thank you!
Yes it will. This is called continuety test. You can also test electrical cables just make sure they are not plugged in the 110v ac or 220. You can also test the switching sides on relays , you can also test other switches as well. Multimeter is to me a must have. Makes life so much easier and prevents one from making costly mistakes.
It's an ohms check. To test resistance, power should be off. It's also a great way to test if power is short to ground also.
@dewilliams2012 thank you!
I just that same voltage meter 😍
How do you know a nox sensor is bad if its not leaving faults code we keep seeing cars with hi nox faults but not exactly saying whats wrong is there an off car test that can be done
not all fuses are live wen testing them ie lights radio etc etc, test light safer in long run, but nice clear in struction thanks 4 being a help,.
Do they all beep?
Nice....I used to always have to pull out fuses to see if they were good....This is much faster. Awesome!
Yo yo yo what do you do if there is just not any power going to the fuse
Keep tips coming
This in theory could damage a cheaper meter, unless you disconnect the battery first. With a fuse blown you could have 12V and high current available. Not a problem testing good fuses as there is no potential difference across a good fuse.
Just be aware of a possible issue with blown fuses and the battery still connected.
I have been doing this with cheap meters and bit more expensive. Never had an issue . Working on 12v and 24v vehicles now for 18 years. Many times tested fuses like this. And got a few that was blown that you could see there is defently a short circuit.
@frikkiesmit327 why not measure the voltage on either side of the fuse?
Or even measure a voltage across the fuse? You won't subject your meter to voltage on the resistance range that way.
Any good meter today won't care, but old digital meters and analog meters could be damaged by subjecting them to a voltage while on the resistance range.
Trust me, it happened to me. Yes, I'm going back maybe 45 years, but think what you are applying to the meter!
It's fine to check continuity across a fuse with the power removed, but in your example the power from the battery is still applied to one side of the fuse, any device that the fuse powers up will be taking the other side of that fuse to ground, probably at low impedance, meaning there will potentially be 12v across the fuse, if it's blown. Like I said, modern equipment today won't care, but older equipment could possibly be damaged.
Would you measure a fuse like that on a mains powered piece of equipment while it's plugged in and powered on? Probably not !! And why not? Because of a possible damaging potential across the fuse !! It's the same principal ! If your equipment is modern, i.e., 18 years in the automotive trade, then I would not expect it to get damaged. I go back 50 years! Yes, all my Fluke,Tektronics, Bryman, and even most of the cheap Chinese equipment today won't care. But with something old, you could be taking a gamble.
I blew a tester using this method. You would think nothing would happen when testing across one wire, but if the fuse is open, you may actually subject the tester to voltage.
Stop spreading stupidity
Voltage meters are open circuits between the probes.
mine doesn’t beep what else can i do ?
The meter will act as a bridge between contacts so even if the fuse is blown it will beep as the contacts will have continuity through the meter.
The whole purpose of a fuse is to break that bridge. That literally how and why they work.
@@peterjohnjoseph give it a minute. . . Think. If it breaks in the middle, and you connect a lead to 1 side, through your meter, touching the other side with the other lead, both sides are now bridged. Hence, the meter will bell out for continuity.
Use a test lamp
Yes much faster
Not as practical because power is not always running through the fuses unless the component is on whereas continuity can be tested whether the component is on or off.
it might not be broken; some fuses get power when key/push is set to accessories
A time when engineers showed love to the mechanics who would service the car.
Nowadays, it seems they do everything they can do make everything a pain.
The beep sounds at well above zero ohms, so this is not a good way to check for a solid connection. Just check for zero ohms.
What should I look for if my multimeter doesn't make noise.
I'm glad a bought a powerprobe
This is not the way to test fuses accurately, it is possible to get a “back feed” this way from the circuit it is connected too due to shared circuit, can lead you down a rabbit hole.
So if it says the fuse is bad, you remove the fuse and test it again with the probes on the fuse leads.
Whatever.
If you get a backfeed then meter will display a - on screen and OL ( overload) . I have never gotten that when testing fuses like this. Ive been working on vehicles for 18 years and did test fuses the same way as in video
@@frikkiesmit327meter will not read OL if there is back feed. If there is back feed you will get a reading. It’s best practice to always remove the fuse. Yes it’s faster to probe right across it but in the case there is some back feed like stated your going down a rabbit hole.
But if I changed the fuse and test the fuse port and there is no power there then what
Then check if theres maybe some other main fuses. Check also on back if the wire that goes into port is still secure. It has happend on some cars like a polo v/ wagen which the factory through they were clever to make sure the wires going to fusebox was under tension. So that caused a wire to pull halfway out so fuse didnt even touch the terminals. Which caused the cars centre lock not to work.
And also if the terminal doesnt securely clip inside fusebox than what happens is when you insert fuse, you pushing the terminal away leadinh to bad and no connection.
Thanks.
Thank u man!!
No problem!
To test continuity, you need to be in series with the circuit. This is testing in parallel and not a true reading.
I just use a test light, either put the black on a ground or if I can get to the neg battery post. I mean. This is good to know To I guess.
Just dont use test light on any of the wiring harnasses. You can easily trigger and deploy airbags of a vehicle. It happend to one technician few years ago. Test light the old type which just consists of globe, they are basicly a short with little resistance. The other test lights with leds are safer.
@@frikkiesmit327 well I work on equipment only. lol. But good point.z
You will be surprised how many people dont know this simple test procedure . And some you can show and they dont care to learn it. They rather call the one that knows 😂
It’s not about “caring to learn it” 35 plus years forklift/plant & I’ve picked up good pointers here on RUclips, I’m saying potentially a shared circuit, or someone who has bridged into the circuit further in, or a relay that has snapped internally etc etc could cause a back feed, been in that position. Also, by testing across the fuse, you can’t see the deterioration across the fuse weakest point, been in many a situation where the circuit stops, being mobile a engineer, 2/3 hours later when we turn up fuse has cooled & 2 pieces of fuse are now touching, no fault found, circuit heats up fuse opens across break, don’t have to have a blown fuse to have no circuit, not personal, but I’d rather do my due diligence, job done right, no repeat calls, have a good day.
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🤔 This is incorrect. Continuity should only be checked with no power in a circuit. A (non led) test light applies a load to the circuit and is more effective than your suggestion.
My multimeter doesn't beep
That's a terrible way to check a fuse
I'm working elastic work
Thanks man, bitch been take out each fuse then check it . I was thinking about how much time it's taking me for fuses under the hood, then under dash.
Thanks man
I rather pull out every fuse, their cheap anyways. If you have a Short? When you put the fuse in it will Arch.
That does not work in all cases you have to eliminate line and load on the fuse probably just confuse you must remove it
I had some problem with a 30amp fuse, looked and acted completely normal, had power flow and everything, buy as soon as there was heavy draw I kept having issues, I replaced and isolated everything just to find the fuse was faulty and half connected 😅
@@codypalmer2732fuses breakdown/wear out but don’t blow until what you describe happens, for us mobile engineers the circuit has cooled down, fuse element touches, continuity ok, experience tells me when chasing this type of fault renew fuses.
Do all fuses brake if their bad or not
Do the same thing on volts look for the same voltage on both sides of the fuse 😂
I hate when people THINK they know and try to teach others
No my fuse is in good condition but no power
All multimeters don't have a beep. You're gonna have people changing out all their fuses when they are not bad
I hope they do
😂 if they don't have a continuity check mode, they cant choose the "beep" setting.
Then just use voltage mode
If there's 12v coming through then it's working
Use a test light 100% faster
Not a good way.. use voltage setting..like others say. Fuse good should have zero volts across else 12 volts.
He said the fuse is “broken”. 🤦🏻♂️
Not all meters have a beep bud
Your supposed to set on dc volts not continuity
Continuity looks like?!.@worst signs ever made.where not aliana❤
Bro work1 sadfannunglan
Ohhhhw, that's so wrong
How?
@@alecpajor9273you can get a back feed from the circuit giving a false reading.
Blown fuse, one side will be 12volts ,the other side earth via the load. Resulting in a blown fuse in the voltmeter. Better to test for voltage to ground.@@alecpajor9273
Yeah tell us how thats so wrong? You more than welcome to remove each fuse by hand and check.
This is bull shit… one major flaw that isn’t mentioned. You MUST have the battery disconnected from the vehicle or a resistance test won’t work.
But the next major flaw is that if you are checking fuses you are looking for a reason that something in the car isn’t working, right? Well, if you use this method correctly you will only know if the fuse is good or bad. You won’t know if there is power at that fuse.
Just use a test light with a incandescent bulb.
False
Can you check fuses to see which one is draining your battery with this same method? Here is the thing. I don't know shit about electricity and eveyrhing about it confuses me. Everybody here on you tube on some different type of testing and setting on the multimeter.
NO.
Read a book, use the internet, take a class or watch a lot of RUclips videos to learn about electricity and how to troubleshoot electrical problems.