Hi folks,
I purchased a 2001 c5 coupe Saturday that had been garage kept and had 40,000 miles on it. I drove it home and it ran great. I got in it on Sunday and the battery was dead. I measured voltage and the meter showed 2.3 volts. The Delco battery was 5+ years old so I replaced it with a new one. Every thing seemed fine. Everything worked as new. I got in the car today and the new battery was dead. I charged it to 13.2 volts and used a multi tester between the negative battery cable and the negative battery post to measure amp draw. The reading was -5.4 amps. I disconnected the alternator and pulled every fuse and relay from both fuse boxes one at a time. The only fuses that made a noticable drop in amp draw were the #5 Radio/CD player fuse, the #25 BCM- Ignition 1 Instrument Panel control fuse and the #27 HVAC Controls fuse. This dropped the amp draw to -.68 amps. I installed the #25 and #27 fuses back and left the #5 Radio fuse out. The reading was back to -4.5 amp draw. I let the car sit for 30 minutes to allow the BCM to go to the sleep mode. The amp draw was at -2.2 amps. I checked the battery cables and wiring harness below the battery. There had been no acid leaks. There was no moisture around the BCM. All wires looked like new. I connected a scan tool and no codes showed up. Everything checked out ok. I don't think there was a problem with this car before I bought it. It was showing fuel milege and trip data in the display. Any help will be greatly appreciated.

 

Thanks for the info. Yes, I had the meter connected for the 30 minutes without disturbing anything. I may have multiple problems. I have cleaned the grounds but that hasn't helped. I'll keep trying. Thanks again.

 

Thanks for the info 8vette7. I did check all lights and light switches. I still have a 2+ amp draw after everything shuts down. All relays and fuses related to the seats and radio/cd have been removed. Maybe I need to check the solonoid switch or the ignition switch.

 

Things that I have seen cause issues are:

Drivers seat contorol switch mallfunction allowing the seat motors to run after shut down!!!

Unplug the seat control connectors and recheck the readings.

BC

 

Yes, the trouble was in the seat motor circuit. I disconnected all seat fuses and relay and battery seems to be holding a charge. Thanks for all your help.