Let's play: Guess the electrical gremlin in the Gremlin!
 

Ok, I have a 1975 AMC Gremlin, all original, 232 straight 6, not even 40,000 miles on it. A few nights ago, I was driving home from a friend's house, alternator died (showing 12.6 volts at the battery when running), made it home, charged the battery and changed the alternator the next morning.

First replacement alternator charged the battery fine at 14.7 volts, but the ALT light was staying on when running, but was off when the car wasn't running but had the switch on, which is also not right. I took it back and had it tested, and the diode pack was bad out of the box, no big deal, it happens. Got the replacement.

Second replacement also charges the battery fine at 14.7 volts, but the ALT light is still acting the same. It tested fine though at the store and is definitely not the problem.

A few more very important clues:
I noticed my gauges are reading low and the BRAKE light in the cluster, which is supposed to come on along with the ALT light when the switch on and engine off, isn't coming on either. If I start and stop the engine a couple times, I can occasionally catch a little flicker of the BRAKE light just as the engine starts.

This is a simple Delco 10SI 3 wire internally regulated alternator, one big wire goes to the battery for charging, one goes to the idiot light and one goes to the ignition switch for voltage sensing.

I have already solved this, and I feel extremely stupid now, lets see who can guess the problem.

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

I'll bite, the exciter wire was pinched in the brake pedal. and were and the pics of this beast?

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

The idiot light wire from the alt to the dash is in short.

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

No wires pinched, broken or shorted.


Pictures of it here:
http://s136.photobucket.com/albums/q...t1787/Gremlin/

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

Excellent specimen, did you do the restoration? How about a missing woodruff key, pulley spins without turning the alternator?

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

Nope, I did it the cheap way, I bought it finished. Really all that has been done is a repaint, which was done about 7 years ago.

Nothing wrong with the 3rd alternator at all, it was charging perfectly.

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

Geez... then is a real gremlin messin up with your car!:D

Btw, nice restoration. Is that an inline six?

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

Do you have a diode/transister thingie in the line going to the gauges like my TVR is supposed to have?

Why don't you come diagnose its charging issues since your a gremlin master! The prince of darkness won't stand a chance!;)

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

The voltage regulator? It has one, but it was fine.

Does anything say "Lucas" on it? If it does, you have found your problem.

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

we had a 74 Gremlin X (orange and yellow) with just an AM radio and no AC when I was a kid. i always loved the "remove the key while it is running" trick. :lol:

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Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

Key related?

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

Yeah, those old GM ignition locks get worn out quick. Mine was messed up just from sitting for years with the key in it, the tumblers froze in place so a key wasn't required when I bought it. Luckily those locks are available almost anywhere, since it is just a GM part, they are also dirt cheap.

Nope.

Think simpler, much simpler.

Yep, just a 232 inline 6 with a tiny little 1 barrel carburetor, maybe 100hp on a good day. Plenty of low end torque though. This is the same design as the famous Jeep 4.0L that they used all the way into the 2000s. Makes for a great daily driver and with a 22 gallon tank, I see a gas station about once a month.

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

Disconnected battery <:)

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

No a diode resitor pack in after the idiot light before it goes to the other items on the circuit.

Yes there are plenty of Lucas parts on my TVR. All of those have been issue free suprisingly.:D

Re: Let's play: Guess the electrical gremlin in the Gremlin!
 

Oh, of course..! You switched the wires in the alternator, thats why the light remained off when engine off but swith in ign position, and on when engine running.:D