How to Fix Electrical Problems in Your Car (Ground Fault)

How to Fix Electrical Problems in Your Car (Ground Fault)

one, two, three, four! Rev up your engines! It’s time for the Scotty Kilmer Channel if your car’s having strange electrical
problems then stay tuned, because today I’m going to show you how to use a
simple voltmeter to find electrical problems in your car, now realize that in
your car the battery supplies both positive power and negative ground power,
and many times when weird things happen to your car, like you step on the brakes and
the parking light comes on, you have a ground wire problem, which can often be
hard to find, now even I can’t see electricity, so you need to test for it,
using this voltmeter you can find bad grounds quickly,
first hook the meter up to your battery, positive to positive, and negative to
negative, and in this case we get the battery voltage of twelve point eight
six, which is normal for a good battery, now say you want to check to see if
the engine is grounded correctly, it’s easy, just take the negative test lead
off the battery, and then clamp it on something solid like this metal part of the
head, and as you can see it’s still exactly twelve point eight six volts,
that means that the engine is perfectly grounded when the engine is shut off, but
that’s not a good test, really you want a dynamic test to see if it works when the
engine is running, now to do that we have to retest it with the engine
running to see what the voltage is with the alternator running, which in this
case is 14.26 or 14.27 it keeps moving around,
then we’ll take the negative terminal off again, and hook it up to the block
and see what the reading is, in this case it’s 14.27 so it’s good when it’s running
too, now if the reading had been 4/10 of a volt or more in differential, there
would be a problem with the grounding wire, but it’s the same so that grounding wire
is okay, for instance if it would have read 13.06 volts that would have meant it was more than 1 volt less, which would
mean there’s a problem in the grounding wiring, now realize that there’s ground
power wires everywhere in a car, like this one on the back of the firewall
here, and you want to test them with the engine off, and with the engine on, to see
if there’s a problem either way, and if you find that either one of the readings
is 0.4 of a volt or more off, that means it’s a problem in that grounding wire,
and you got to trace the wiring or the connectors at the ends, to see if they’re
corroded or loose, because if you do have a bad ground wire, when you use that
device, it’ll often try to draw power from other devices and turn them on, so
weird things could happen like you step from the brakes and the parking lights
will come on, because it’ll start to turn those devices on, when that happens you
almost always have a ground system fault somewhere, sure there’s grounding wires
all over the place, like in the trunk of this Mitsubishi, you can see they run off
the lights, but now that you know how to test them with a voltage meter, it’s very
easy to find out if the grounds aren’t working correctly, and I know some of you are going to ask, why do I have to test with the car off and the car on, well
that’s because a weak ground wire might work ok with the car turned off, but when
all the power is running through it, if it’s got a bad connection or a short and
end on it, it won’t take extra power and you’ll see that by a bigger voltage drop,
knowing there’s a problem, so just like any other machine, it’s much better
testing them when they’re working instead of when they’re just sitting
there doing nothing, and the act of dynamic test is much better than static
test, after all you want everything to work on
a car while you’re driving it, you really don’t care what it’s doing it’s just
sitting there resting, so now you know how to do a voltage drop test on
grounding systems, just remember if you have more than point four of a volt
difference, you got a problem in the grounding system, and remember if you’ve
got any questions just visit the Scotty Kilmer channel and I’ll answer them as
soon as I’m done drinking some of this moonshine!

About the Author: Michael Flood


  1. Things I used in this video:
    1. Voltmeter:
    2. Common Sense
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    4. My computer for editing / uploading:
    5. Video editing software:
    6. Thumbnail software:

    🛠Check out my Garage to see what I use every day and highly recommend:

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  2. Great video!!! I know it's kind of an old video, but I have a problem with my 2012 TOYOTA 4RUUNNER!!! My voltage needle on the cluster fluctuates up and down with or without accessories on but even more so with them on!!! Even in park at idle with nothing on!!! I come to a light or stop and it drops quite a bit then goes back up to the center of the gage!!! Would you say this problem is due to a bad ground, a short, or some kind of open circuit problem??? I have taken it to the dealership and they can't seem to figure out what's causing the needle to fluctuate like that!!! Your help and advice willl be very appreciated to solving this problem!!! Thank you and your videos are always fun and very helpful to watch!!! 👍👍👍

  3. Hi Scotty. I got 24V system nissan safari y60 1988 and I connected the multimeter to negative battery terminal and ground on frame giving me output 12.5 V. That should be zero shouldn't be? Positive battery terminal and negative ground giving me 25V output normal there. What could be a problem? I got a battery warning light on. Thank you.

  4. I jump my car off and battery slowly drain and car won't start back up after jump off I change the alternator and the battery both brand new car still won't stay crank up I have 2001 dodge caravan 3.3L

  5. Hey Scotty;
    I have a 2002 Honda Civic Ex 1.7 stick shift. Lately it’s been having a no crank, no start issue and have been resorting to pop-starting it. The battery test perfect, we thought it might be the starter but the starter seems fine with the exception of a loose connection. We cleaned the tightened the connection line. The car was fine for a few weeks but has begun intermittently having the no crank no start issue again. Please give me some possibilities.

  6. I recently bought a Lexus 2004, the low beam lights don't turn on only the high beam. I noticed that the fuses were burnt on the gray part of the fuse. It also makes a buzzing sound when I switch on the lights what can be the problem?

  7. What about my 02 corvette dash lights going on for no reason, service engine,reduced power, low fuel,service abs,service traction control,low voltage, etc.

  8. Question: If a ground wire is removed from the engine, what kind of problems could happen, how would it affect my car?

  9. When the main ground is off the head that is not a good ground, maybe when the vehicle is new but as it ages electrical problems will start.

  10. Good helpful video 👍 easy to understand and keep it entertaining!
    Nice stingray also. Once I'm done with this jetta I'll be troubleshooting the black Corvette starter issue 🤞

  11. I have a 2003 Hyundai Tiburon
    my left tail light went out and everytime i put in the left tail light fuse, it blows and so does my room lp fuse as soon as i try putting them in. where should i start checking

  12. Scotty, This video was about staying grounded, no getting lit up… Awesome video, You deserve a couple good swigs…

  13. Hay Scotty, how do you check when one day its the. Left window motor not getting power a few days later its the radio, then the right window motor, then the starter. How do I check to find what is causing this without replacing everything

  14. Hey man I have an issue maybe someone can help. I have an 06 Chevy 2590 5.3l v8. Issue is it randomly pops up saying engine coolant hot, engine overheated. But immediately after letting off the gas the gauge returns to normal. Now everytime this happens, my oil life goes to 0 and it says change engine oil. I've replaced temp sensor, thermostat, water pump, alternator and when I turn on ac the fans work, but not without ac. Please help..

  15. Change the title from''How to Fix Electrical Problems in Your Car (Ground Fault)'' to'' How to check if your car has a ground fault''.

  16. Scotty, I’m testing an ac compressor with a power probe three. I know my probe is saying a I have voltage drop and poor ground at the connector going to the compressor, however I’m having trouble figuring out why. Any help?

  17. My radio in my truck take to long to go off. How can I find the problem. I know it’s a electric problem. How can I test for that? It’s draining my battery in my truck. Please help

  18. Hey Scotty I'm a subscriber and I also like and watch a lot of your videos is are very helpful so thank you for that

    I have a situation you're in I think you'd be able to help me so here is a scenario

    I have a 1998 Ford Mustang V6 I have replaced the alternator the pigtail from the altimetre the battery as wellAlso took it to my local mechanic he hooked up his voltage meter and he said everything was checking out OK check the fuses check the wires he says everything checked out OK but I think they're still something that I can do please help me

    And it's still not working pretty frustrated not knowing what to do

  19. My car dude has a problem with the antenna an the speakers sound like electric is going all in the car what could it be should I disconnect and antenna

  20. How bout when you turn the AC on and the truck dies 2mins later. Leaving you stranded for 4 hours while you try everything u know to figure out why the fuel pump wont prime. And then it just starts for no reason

  21. i have a2002 jeep liberty the lights stay on i changed the comb switch still have lights could their be a short

  22. Im not very good but i thought i could do a voltage drop by hooking a volt meter to ground on battery and the other voltmeter wire to the engine would this show the voltage drop also?

  23. Wow, simple test. Alas, something the simple solution guy, who may be slightly leaning towards the Mr. Magoo direction doesn't know the two other steps you so graciously provided. Thanks again Scotty.

  24. Hey scotty, just got a 2005 honda accord and I remember using the ac just to try it it was winter so didn't need it and the radio would work sometimes I would have to turn it off and on a lot of times and sometimes it would work… but I noticed If I hit a bump it would make it turn off.. now my ac doesn't work it blows but not cold at all and my radio doesnt work at all either, I'm guessing I have an electrical problem? Any suggestions?.

  25. Hey Scott I have a 2005 Chevy Malibu that cranks will go into reverse and neutral and want shut off but as soon as I put into drive it cuts off please help me don't have money for shop

  26. Hi Scotty I have a 2013 Malibu Eco having electrical issues and auto start/stop doesn't help alot of people saying could be battery cables but they look fine need help

  27. Electrical problem? Easy. Install jumper wire in place of fuse from circuit you are having problems with and just follow the smoke.

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