: 96 SLS Electrical Charge System Gremlin



jersey jay
11-13-08, 07:59 PM
I have a 96 SLS with the 4.9 Northstar with 40K on the clock. I just replaced the alternator and battery with a red top. The problem I'm having is after I leave the car sit idle for a week it's stone cold dead. I'm not throwing any codes. I show no draw when the car is off along with my Tech II showing no charge system faults.

I've checked all the relays, fuses and grounds along with wiring a new plug that goes into the alt. Strange thing being that if I garage the car the battery will remain charged for 2-3 weeks before fully discharged. If I keep the car on a trickle charger there are no issues.

Charging system after startup is anywhere from 13.5-14.2.

PCM, maybe?

Ranger
11-13-08, 08:11 PM
A/C Delco alternator? Is your battery under the rear seat or under the hood? If it is under the seat, does the battery have the proper vents? If you are showing no draw, my only guess would be a bad battery.

jersey jay
11-13-08, 08:19 PM
A/C Delco alternator? Is your battery under the rear seat or under the hood? If it is under the seat, does the battery have the proper vents? If you are showing no draw, my only guess would be a bad battery.

Brand new Optima Red Top which I replaced with a 2nd within a week being I thought the new one was bad out of the box. Battery is under the hood so venting isn't the issue. Aftermarket alternator installed for higher voltage output.

Ranger
11-13-08, 08:26 PM
Possibly a problem with the alternator, but that's just a WAG. I have no other ideas.

jersey jay
11-13-08, 08:37 PM
Possibly a problem with the alternator, but that's just a WAG. I have no other ideas.

I replaced it with a new one as well as I felt the first one was bad out of the box.