1997 GMC Safari altenator?

MICHELLEBRGHTN

MEMBER
1997 GMC SAFARI

Electrical problem
1997 GMC Safari All Wheel Drive Automatic

please help my battery keeps draining while driving. I have replaced the altenator battery and belt. And stil have te same problem. Have had al new parts tested and retested. Had friend do voltage meter test andsaid alt isnt cgarging battery took every thing out and ha tested was told all were good reinnstalled checkecked all connections grounds and still havingh same problem when recharge batter and turn on car only goes to 9 on dash volt meter and slowly drops no matter how long I charge itup when first put on new belt after replacing alt and battery ran great for 2 weeks and all sudden problem was back! Just cant figureit out? What to try next

1 Reply

JDL

MECHANIC
16,098 POSTS

Welcome to the forum, use a digital multimeter. Take a reading across the battery posts, everything turned off, a fully charged battery should show around 12.6 volts. Take a second reading across the battery posts, engine running. Also check the reading at alternator bat terminal. The second reading should be higher than the first, if not the alternator isn't charging for some reason.

Also, there has to be excite voltage at the alternator L terminal or the alternator won't charge. Does the charge lite on the dash work?