: 1980 Coupe Deville Generator Light Problem



Buddy Scott
11-19-10, 07:08 PM
My Deville has a GENERATOR light that shows dim during highway driving and slightly gets brighter when idling. There's no problem with charge on battery and alternator makes no screeching sounds. I took it to a shop and the alternator passed all charging tests. The lead from the positive battery terminal to the alt showed heat damage at the butt connector. I replaced the wire with 10 ga. and the butt connector. The alt plug and wires appear to be in good condition with no signs of damage.
Any thoughts as to what the problem might be? Diode? Fuse? Generator light short?
Thanks in advance for any advice.

cadillac_al
11-19-10, 09:20 PM
I guess it's a bad diode that causes that. My Seville has been doing that for 14 years. I keep waiting for the alternator to just die so I can buy another one.

Buddy Scott
11-19-10, 11:31 PM
Is it possible to just replace the diode without doing the whole alternator? Showing no signs of charging issues or anything.

deVille33
11-20-10, 10:20 AM
You have to open the alternator and replace the bridge, which is a pack of 6 diodes. If you have a service Manual it will help you understand the alternator's workings better and show you how to check out the individual components of the alternator.

cosmo
11-22-10, 08:48 PM
You CAN replace the individual diodes, but you'll have to find a supplier first.

Cosmo

1980coupe
11-23-10, 12:01 AM
Just get another alternator. I have had the same problems on mine. It was tested both on and off car and it passed, once you get it, the light will no longer be lit.

carnut
11-23-10, 12:07 PM
Get a rebuilt A/C DELCO brand unit, a better rebuilt than most.

Buddy Scott
11-23-10, 03:05 PM
The price to get a rebuild kit was $20 bucks. It had the diode and such. Seemed pointless without the bushings. The new one was $50 bucks, Duralast with a lifetime warranty. Changed it on Autozone's lot so I didn't have to pay core fee. Light's out. Crisis averted. Though I will say that damn rod the houses the bottom bolt is an SOB to pry into place. Thanks for all the responses.

carnut
11-23-10, 11:23 PM
You know I try to point people in the right direction but they dont listen!!! A DURALAST wont last! a DELCO will. Be prepared to replace this alternator again in the near future, lifetime warranty or not. Personally I want to fix a car the first time. My time is worth something. A DELCO costs more because its a better quality rebuilt.

1980coupe
11-23-10, 11:41 PM
The price to get a rebuild kit was $20 bucks. It had the diode and such. Seemed pointless without the bushings. The new one was $50 bucks, Duralast with a lifetime warranty. Changed it on Autozone's lot so I didn't have to pay core fee. Light's out. Crisis averted. Though I will say that damn rod the houses the bottom bolt is an SOB to pry into place. Thanks for all the responses.

I hear you there buddy. That bottom bolt is a Pain in the Ass!! Hey on yours do you have a rear bracket that bolts up somewhere to the engine? I saw one in the salvage yard (80 also) and when I looked at mine when I left it doesn't have it???