Small electrical fire...help!

[hh65flyer]

Pulled into the garage tonight smelling electrical burning (not a great feeling). I traced the source to a rather heavy gauge wire that runs from the hot side of the starter solenoid into the harness that goes under the battery tray. This wire had what looks like a screw-together heavy fuse in it. It is seems to have done its job as it is now melted through. Downstream from this fuse, the wires split (Blk/Orange) and head into the harness and under the battery tray.

This all looks pretty factory (91 LX) with the exception of that fuse. Service manual shows several fusible links in this area but not an actual fuse. This is (was) a pretty big fuse, like the kind you see on big car stereo systems.

I checked to see if there was continuity to ground (a short) but didn't find anything there.

Any suggestions on what to do next?

Thanks!

 

[89rdgt]

I would next do a very good visual of the harness. Make sure its not rubbing on anything it could ground out on. Try testing for countinuity while wigglying the harness. It could be a intermitant problem. If everything checks out fine put a new fuse in and retest.

Remember a fuse doesn't blow for no reason.

Good luck.

 

[HISSIN50]

sounds like an alternator wiring issue. Tom's awesome diagram might help ya out (check the lower right side of the page).
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

someone might have fried the fusible link in the past and then used a fuse in lieu of a link (i would).

good luck.

 

[hh65flyer]

Thanks guys. I'm going to see if I can track it down after work today. That diagram should help and I didn't think to wiggle the harness.

Matt

 

[hh65flyer]

Turned out to be an in-line connector not fuse. Someone had spliced two lines together and that union got hot and melted. I replaced it with a 30 amp, two post, circuit breaker and all new wiring. I hope that's the only issue.

Thanks again for the help.

 

[Daggar]

Well it sounds like your fix is a good one. Doncha just grit your teeth when someone fixes a problem with a hack job? hehe

 

[HISSIN50]

was it the alternator wiring? some upgrade write ups have people connecting two such wires, IIRC. others in here have posted that doing so is not cool. i dont know more but wanted to toss that out there as something to chew on.

good luck.

 

[hh65flyer]

Yes Hissin, it was the alternator wiring. My Circuit Breaker didn't turn out to be the right fix either as it kept opening and I was getting a low battery light. So I installed a fusible link of the appropriate size and will try it tomorrow. The link just seems so small (14 G) coming off of a 10 gauge wire that passes so much current!

The breaker was constantly opening (I should have thought 30 amp wasn't big enough) in an effort to keep the juice up as the battery was continously being drawn down by the motor and electric fan. I also have underdrive pulleys which aren't helping either.

Maybe it's time for the 3G upgrade. I guess I should do a search and see what is involved with that.

 

[HISSIN50]

Yes Hissin, it was the alternator wiring. My Circuit Breaker didn't turn out to be the right fix either as it kept opening and I was getting a low battery light. So I installed a fusible link of the appropriate size and will try it tomorrow. The link just seems so small (14 G) coming off of a 10 gauge wire that passes so much current!

The breaker was constantly opening (I should have thought 30 amp wasn't big enough) in an effort to keep the juice up as the battery was continously being drawn down by the motor and electric fan. I also have underdrive pulleys which aren't helping either.

Maybe it's time for the 3G upgrade. I guess I should do a search and see what is involved with that.

im a bit confused now. the stock alt is a 65/75 amp unit. so 30 amps would be insufficient.

the stock wiring is pretty marginal, IMHO for a stock alternator. i have not felt great about it either.

good luck with it.

 

[Funanin]

Replace it!

Sounds to me like a surging or short from your alternator wiring... If you still have the stock alternator, replace it with a single power wire one that runs straight to the battery. It will bypass all that wiring harness crap that melts. I had an alternator fire in traffic one time, and saw the fire under my hood thru my cowl cutouts and had to jump out of my car. Then I told my gf to stay in the car, as i openned the hood and stood on the bumper and proceeded to piss on the fire to put it out, since i had no water. Pretty embarrassing, but i saved my car.

 

[hh65flyer]

Yikes! I have a hard enough time peeing under pressure during annual whiz quiz let alone when something is on fire. BTW, peeing on electrical fires probably isn't a good idea if you ever want to have kids!!

Hissin, you are right...30 amps was never going to be enough.

If this doesn't work, I may try Funanin's idea. I think I saw the kit on 50resto.