My buddy has a 1990 corvette with a L-98. A few weeks ago coming home from a car meet in traffic, his alter. decides to go out on him. He was able to make it home with needing a tow. He replaced the alter. a few years ago with a reman. Delco 105 amp. Everything was fine after that. This time getting the same replacement and installing it, he noticed his amp guage in the car was acting different.
After the car was warmed up and everything was turned on in the car to put a load on the battery, checking the voltage at the back of the alter., it was a 14.7 at idle, and the voltage at the battery was 14.5. Then when turning on the A/C the guage inside the car would jump up and then back the the charging position, which it never did before. Checking it at the back of the alter. again this time it was 14.2, and at the batter it was 14.0/13.9 and dropping it seemed.
Had the alter. bench test and put a load up to 80 to 105 and everything was fine, it was charging, nothing wrong at all. My question is, I know that having the lights, and radio on and then turning on the A/C, should the voltage drop like that at idle? Plus the volt guage never jumped like that before until now, could there possibly be the relay in the A/C unit going bad?
Any suggetions or ideas would be very much appreciated! Thank you! :confused:

 

I just went through this last week. I'll skip the story and go to the fix. I changed the alternator and recharged the battery. All the little gremlins present before the R&R went away. Even though he put on a different alternator, my money is on the voltage regulator in that alternator. Have him try a different one, and be sure the battery is fully charged.

 

Yes , definatly...Ill go through 3 or 4 sometimes at work if people dont like the gauge jumping around.Even though nothing is really wrong and it would probally last for years, something about the gauge moving around makes people nervous when they are 20 miles offshore.... :lol: