Electrical question
Thread Starter
Melting Slicks
Joined: Mar 2010
Posts: 2,967
Likes: 43
From: Bradenton Florida
2017 C4 of the Year Finalist
No-IL Events Coordinator
St. Jude Donor '12-'13-'14-'15-'16-'17
Electrical question
Already posted in the c-4 section but was wondering if anyone local has an opinion.
On the way to FunFest this past weekend my 94 blew the valet fuse which powers the transmission solenoid packs and also feeds the alternator. I have dissected the wiring, took all of the wiring and solenoids out of the transmission, have that complete circuit disconnected, removed the PCM and battery from the car and still had a dead short going from the fused side to ground. This morning I took out the alternator and as I disconnected the regulator plug from the alternator my circuit finally went open. OK shorted alternator I thought. Just had it tested at 2 different shops and both tests say the alternator is good. The only things on this circuit are the feed for the field on the alternator and the feed for the trans solenoids. With everything out the circuit is clean. Even with the fuse blown the alternator was still working with no field being fed. So even though it tests OK, I think the regulator has to be shorted internally. There is no other place for this circuit to pull ground from unless a wire has chaffed. Which I just confirmed is not the case with my last test. Has anyone ever seen this before? Also with the feed being open how is it getting a field voltage? I just spoke with a re-builder in Algonquin and he is stumped too. His only suggestion was the regulator has shorted internally in a way that it is still fielding and thus charging.
Weird....
On the way to FunFest this past weekend my 94 blew the valet fuse which powers the transmission solenoid packs and also feeds the alternator. I have dissected the wiring, took all of the wiring and solenoids out of the transmission, have that complete circuit disconnected, removed the PCM and battery from the car and still had a dead short going from the fused side to ground. This morning I took out the alternator and as I disconnected the regulator plug from the alternator my circuit finally went open. OK shorted alternator I thought. Just had it tested at 2 different shops and both tests say the alternator is good. The only things on this circuit are the feed for the field on the alternator and the feed for the trans solenoids. With everything out the circuit is clean. Even with the fuse blown the alternator was still working with no field being fed. So even though it tests OK, I think the regulator has to be shorted internally. There is no other place for this circuit to pull ground from unless a wire has chaffed. Which I just confirmed is not the case with my last test. Has anyone ever seen this before? Also with the feed being open how is it getting a field voltage? I just spoke with a re-builder in Algonquin and he is stumped too. His only suggestion was the regulator has shorted internally in a way that it is still fielding and thus charging.
Weird....
Racer
Joined: Feb 2012
Posts: 418
Likes: 7
From: Sugar Grove IL
St. Jude Donor '12, '15
Years ago I had an alternator that had an internal short, it gave me all kinds of headaches trying to figure it out what I thought was other electrical gremlins, I finally just put a new alternator on as a process of elimination and everything was fine again.....You might just want to try that
Team Owner
Joined: Mar 2007
Posts: 35,095
Likes: 2,086
From: Right Corner Pocket of Illinois
No-IL Events Coordinator
2026 Corvette of the Year Finalist - Unmodified
2025 C6 of the Year Winner - Unmodified
2020 C6 of the Year Finalist - Unmodified
2020 Corvette of the Year Finalist (appearance mods)
2019 C6 of Year Winner (appearance mods)
2018 C6 of Year Finalist
St. Jude Donor '12 thru '26
Sounds like a cracked connector at the alternator to me…
Thread Starter
Melting Slicks
Joined: Mar 2010
Posts: 2,967
Likes: 43
From: Bradenton Florida
2017 C4 of the Year Finalist
No-IL Events Coordinator
St. Jude Donor '12-'13-'14-'15-'16-'17
