Fuse blow out, why?

XiongGuy91

Member
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'02 mazda protege5
The headlight fuse keeps blowing out on my P5. Why is this? I have switchback LEDs for my turn signals and they worked just fine until today. I tried putting back in the incandescent bulbs and still wasnt the problem. The fuse just decides to keep blowing when i insert in a new one.
 
If it worked before and its not working now, there is a short somewhere. Check wires and make sure that no power wire conductors are touching the car.
 
Oh, so that's what's happening? Didn't know. So i'm assuming you mean the wire or conductor is burned a little? How do i go about fixing that problem?
 
You'll have to trace the headlight wires to find the short. Start at the headlights and trace your way back to the fuse box. Odds are there is a wire that has worn through or a connector is broken. You can also search to see if somebody has had a similar problem.
 
Thanks maxpower. I did some research and looks like an electrical circuit tracer would make that much easier to do, but damn that thing is so expensive! I ain't much of a wiring person so it's going to be a b**** for me.
 
You don't have to use an expensive circuit tracer. You can do it visually. Just follow the wires and look for cracks in the insulation, wires falling out of connectors, etc.
 
You don't have to use an expensive circuit tracer. You can do it visually. Just follow the wires and look for cracks in the insulation, wires falling out of connectors, etc.

+1, Just feel the wires all the way back to the fuse box.

What you are looking for is exposed wire, where the insulation is damaged enough to reveal the internal conductor. Any time it touches the body of the car, its a straight loop back to ground. If that fuse wasn't there, you would be dealing with melted wires or possibly a fire.
 
It could also be your headlight switch, if it has developed an internal short. If you can't find any obvious problems with the wiring, that would be the next place to check.
 
Step one - with a Ohm Meter check for each headlight connector to see if BOTH wires are grounded. Then check for a headlight shorted. There should be resistance. Measure both and report back.

Step Two check at the relay and then the fuse. (this will isolate which wires you need to inspect.
 
The fuse that blows out are the "tail" in which it is also the driving lights that wont come on, therefore the dash lights as well. Either way i'm still searching for that short or exposed wired area and tape it back up with electrical or some kind of insulation i assume? Well if doing this whole wire tracing thing fails i'll just purchase the expensive circuit tracer to save me from a headache and return it. haha
 
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The fuse that blows out are the "tail" in which it is also the driving lights that wont come on, therefore the dash lights as well. Either way i'm still searching for that short or exposed wired area and tape it back up with electrical or some kind of insulation i assume? Well if doing this whole wire tracing thing fails i'll just purchase the expensive circuit tracer to save me from a headache and return it. haha

Try replacing the headlight switch. I had one go bad once in another car, and had the exact same symptoms you're describing. Both Autozone and O'Reilly carry it, and if it doesn't fix the problem you can return it.
 
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