Alternator not charging
Thread Starter
Race Director
Joined: Feb 2001
Posts: 13,911
Likes: 101
From: Manassas VA
NoVa Events Coordinator
St. Jude Donor '14
Alternator not charging
89 6 speed.
Battery light came on recently. I've done the following to test/trouble-shoot the issue.
1. Pulled battery and the alternator for testing. They both tested OK!
2. Voltage off the rear terminal is 0.56 with car running.
3. Voltage at the large red wire in the connector to the alternator is around 12 with the car running.
4. 12-11.5 volts to the blue wire with the car running
5. 12 - 11.5 volts to the brown wire with the car running.
6. 12 volts at the “gauge” 10 amp fuse
7. No voltage at the "inst" 3 amp fuse.
I did a search and found this:
http://forums.corvetteforum.com/show...ator+blue+wire
There is no C-fan fuse in the fuse panel. The only 3 amp fuse with no power is the inst <-LTP not sure what <-LTP is.....
I think the problem is with the alternator regulator but the Alternator tested fine.
Any help would be appreciated.
thanks
Battery light came on recently. I've done the following to test/trouble-shoot the issue.
1. Pulled battery and the alternator for testing. They both tested OK!
2. Voltage off the rear terminal is 0.56 with car running.
3. Voltage at the large red wire in the connector to the alternator is around 12 with the car running.
4. 12-11.5 volts to the blue wire with the car running
5. 12 - 11.5 volts to the brown wire with the car running.
6. 12 volts at the “gauge” 10 amp fuse
7. No voltage at the "inst" 3 amp fuse.
I did a search and found this:
http://forums.corvetteforum.com/show...ator+blue+wire
There is no C-fan fuse in the fuse panel. The only 3 amp fuse with no power is the inst <-LTP not sure what <-LTP is.....
I think the problem is with the alternator regulator but the Alternator tested fine.
Any help would be appreciated.
thanks
Last edited by Bluewasp; May 18, 2006 at 12:27 PM.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Clearly the alternator has no output on the car, but since it tests fine, the problem is likely that the alternator is not getting 12v from the ignition switch which powers the alternator voltage regulator. When I get home and can look at my 87's electrical book, I will be able to offer some tests you can do to determine where the current path is interrupted.
Thread Starter
Race Director
Joined: Feb 2001
Posts: 13,911
Likes: 101
From: Manassas VA
NoVa Events Coordinator
St. Jude Donor '14
I found the problem. There was a broken connector on the large red wire. Looks like someone tired to repair it once before and didn't do a good job. I replaced the connector with one I bought at NAPA (correct size) and now I have 13.7 volts!! 
thanks
thanks
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Originally Posted by Bluewasp
I found the problem. There was a broken connector on the large red wire. Looks like someone tired to repair it once before and didn't do a good job. I replaced the connector with one I bought at NAPA (correct size) and now I have 13.7 volts!!
thanks
thanks
