HELP! Smoking alternator wire!

[Diabolic]

I was sitting in traffic today with the ac on and I start to smell something burning like hot brake pads or a burnt clutch. I drive a little further and notice the smell is getting stronger. I pull over and pop the hood with the car running. The lug on the rear of the alternator, with the big black/orange stripe, is smoking at the lug! The rubber boot has burned completely off. It looks like it goes from there and then splits into 2 fuseable links and into the under hood fuse box. Right to the power lug on the side of the box. So now I have the car home to look at it. Any idea what to look for? Wire chaffed and grounding out? Bad alternator? Gauge looked to be reading normal. The wire goes into a loom so I'm just guessing it goes from the back of the alternator then over to the lug on the under hood fuse box.

1995 Cobra

[Tannerm]

My guess is gunna be a cross wire/grounding somewhere. I effing hate wire hunting, but if you got the time id do it. Secondly, a trip to a close auto parts store wouldnt be bad to have the alternator tested. I honestly dont know how accurate those testers are. Both options i gave were free and id start there.

[Mysticcobrakilla]

Alternators have been known to go up in flames. It could just be a bad/burnt up alternator.

[Diabolic]

Well I stripped the smoking wire from the harness and it looks great! Fuse links look a little crispy. I'm going to replace them. Ok I tested the back post of the alternator with the car running. 37 Volts at the post! I thought the tester was bad so i put it directly on the battery and got 12.4 volts. Back to the alternator and 37 volts again. I'm thinking the regulator is fried. Why didn't the fuse links give out?

[turbostang]

Alternators have been known to go up in flames. It could just be a bad/burnt up alternator.

This.

The connection could have just been loose - which will make it get hot etc. Take the alternator, test it, and replace if necessary - next, replace alternator wire. (Amp power cables work good for this)

[garycrist]

The connector on the power wire(O/B) is crimped onto the wire. After a while it will loosen and create the problem you see. You can run a new wire to the battery or solder a new connector onto the O/B wire.

[Mysticcobrakilla]

Well I stripped the smoking wire from the harness and it looks great! Fuse links look a little crispy. I'm going to replace them. Ok I tested the back post of the alternator with the car running. 37 Volts at the post! I thought the tester was bad so i put it directly on the battery and got 12.4 volts. Back to the alternator and 37 volts again. I'm thinking the regulator is fried. Why didn't the fuse links give out?

37 volts? Damn.. That's impressive. Voltage regulator took a shit.

Think of fusible links like they are a fuse. Amp draw is what pops them. No real amp draw going on without a dead short or something of the like going on. Replace alternator.

[BlackGT]

37 Volts???

Either replace it, or put in a kick-ass sound system since you have plenty of juice now to run it...

[Diabolic]

Well I took in the alternator to get tested and it passed at Oreileys so I took it to the Zone and it passed there too! WTF? I made a new cable and soldered the connections. All new hardware. I'm going to put it back together and try it out. Maybe a bad spot in the old connections or loose at the alt.

[Mysticcobrakilla]

Well I took in the alternator to get tested and it passed at Oreileys so I took it to the Zone and it passed there too! WTF? I made a new cable and soldered the connections. All new hardware. I'm going to put it back together and try it out. Maybe a bad spot in the old connections or loose at the alt.

That's possible but I wouldn't trust those tests. 37 Volts says I'm replacing the alternator.

[BlackGT]

That's possible but I wouldn't trust those tests. 37 Volts says I'm replacing the alternator.

X2. Last thing you want is for the insulation under the hood to catch fire and spread to other wiring and components under the hood...

[Diabolic]

Well I hooked it back up with the new wire and I'm getting 13.2 volts with the AC running at idle. THis is at the lug on the back of the alternator. I'm wondering if testing it with no wire connected made the regulator up the voltage???

[Mysticcobrakilla]

Well I hooked it back up with the new wire and I'm getting 13.2 volts with the AC running at idle. THis is at the lug on the back of the alternator. I'm wondering if testing it with no wire connected made the regulator up the voltage???

$80 alternator is not worth my car going up in flames because the voltage regulator is acting fine now. Did they check the diodes?

[Diabolic]

To be completely honest I don't know. I have a fire extinguisher in the car now. I drive it a lot so I will check the condition of the new boot at every stop. If anything looks fishy I'll go ahead and replace it.

[mustang87]

regulator going bad in alt. mine did the same thing