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How To Test or Check Fuses if they are Bad or Blown.

How To Test or Check Fuses if they are Bad or Blown.

– [Instructor] Hi, Den
here from Today I will show you a video
on how to check the fuses. I’ve had a lot of people ask
me about how to test fuses, check the fuses if they’re good or bad. It’s pretty simple. If you do have any electrical problem, you would want to start
with the fuses first because if it’s a blown
fuse, all you have to do is just replace it with another
one and you’re good to go. Unless you have a short that
continuously blows the fuse. Then you’ll have to
troubleshoot the short. Some cars have, most of the cars have the fuse box on the engine compartment and on the interior of the car. Some have them in the trunk,
some have them under the seats. How to check the fuses, I’ll show you how. You will need a test
light similar to this. It’s a cheap test light you
can get at any Auto Zone or any parts store. You hook it up to the ground
of the battery terminal. Once you hook it up to the
ground of the battery terminal, with this side you would touch the power and if it lights up you’re getting power. You would want to put
the ignition on first because if you don’t, the
fuses that are supposed to get power, they will not light up. For this instance, how to
do it is you touch one end of the fuse. If it lights up and the
other end lights up, that means the circuit
from here to here is good, it’s getting juice all around. From here we’re getting juice to here. From here, to here. So we’re getting power here and here. If you come up to a fuse
that doesn’t light up on one end and on the other end, that does not mean it’s a bad fuse. That could be a circuit
that’s getting power with the headlights on or whatever and obviously they’re off right now. So you can test that or you can check what it goes for and put it on, let’s say, headlights we can put them on and test them. Otherwise don’t replace these fuses if you’re not getting power on both ends. Now a bad fuse, what it’s going to do is you’re going to have power. One end would light up the other end of the
fuse will not light up. So when you touch one
end, it’s getting power. The other end is not getting power. So this is an open
circuit, it’s a blown fuse. Power on one end, power in
the other is a good fuse. Power on one end, no power
in the other is a bad fuse. To replace it, all you
do is just pull it out, you can confirm it’s a bad fuse by looking at the fuse and you can see, I don’t know if you can
see it on the video, but there’s an open circuit
from one end to another. All you have to do is just
replace it with a good fuse. Same amperage. And then you can check your circuit. One end is getting power, the other end is also getting power. So now you have a good fuse installed and you’re getting power
to whatever the circuit needed power didn’t have it before. So this is how you check the fuses. It’s pretty simple. One end has power, the other one doesn’t, it’s a bad fuse and if it doesn’t have power in both ends, don’t replace the fuse
because that circuit probably is not getting juice. It will get juice when you turn on, let’s say, headlights or whatever, in this case, this is a headlight fuse. Thanks for watching. See you next time.

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14 thoughts on “How To Test or Check Fuses if they are Bad or Blown.

  1. how about using an ohm-meter on the not powered fuses from contact point to contact point ( if one has those ), if there is contact or the bridge is burned trough otherwise the have to be taken out and visually inspected.

  2. Very thorough! I visually checked fuses three times in an attempt to fix multiple components that involved two bad fuses. I have been working on my own cars most of my adult life and considered myself fairly decently mechanically inclined. However major fail on my part. I ended up bringing the car in to resolve the issue convinced it was some fuse link in the line out of reach. I did not find the so-called "common break" easily visible in the middle of the fuse head window – if they break along the sides that is where testing with a test light very quickly determines bad fuse from good. And moreover you don't have to spend time pulling them when you have multiple components not working, while the suspected fuse "looks" just fine! Kuddos to you- Can't go wrong this way!

  3. Came here to see what a blown fuse looks like and all you see when its being shown is the red banner that says "subscribe it's free." THUMBS DOWN!


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