I have a 94 929 that looks like it quit charging the battery. It finally died. It will jump off and run fine for a few minutes, and then dies again.

Replaced alternator and jumped it off...It ran for about 10 minutes (That's how far it was from where it died to home).

Replaced battery and charged it. Started and ran fine. Left it overnight. Started fine and ran until the battery was dead again.

Can anyone suggest what to do to diagnose the problem?

Thanks.

 

First thing is to check the fuses...they are labeled:
"METER" which is on the dash fusepanel
"EGI" which is on the underhood fusepanel
The main fuse should be good since the car runs.

There are three wires on the back of the alternator that should be tested for 12V:
WHT/BLK which is hot with the key "on"
BLK/RED and WHT/GRN which are hot at all times.


This will help eliminate a wiring or fuse problem. It is possible to get a bad rebuilt alternator.