Battery getting run down/No tail lights

[rayfinkle5]

Hello,

I've been struggling with my Tahoe for well over a month now. My issue began when it wouldn't start one morning. I took the battery out, tested it (bad) and put in a new one. The truck ran without issue for about a week then wouldn't start again due to a dead battery. Took the truck to a local mechanic. He thought the problem was the ignition so he put a new one in ($241). That didn't solve the issue. The mechanic tried for a solid week to figure out what was going on but eventually told me he couldn't figure it out.

A friend has helped my try to locate the problem too. We've tested the fuses (good) and the switch to the lights (good). My friend thought he had it narrowed down to the BCM. Bought a BCM this morning from a salvage yard and put it in the truck. First issue, the truck started but won't continue to run. Guessing it has to be programmed to the key? Second issue, even with the different BCM in I still had no rear lights. So, I put my original BCM in, returned the other one and drove home. The truck drives fine, I just don't have rear lights and if I don't disconnect the battery between drives the battery will go dead.

Anyone have any suggestions?

Thanks.

 

[rayfinkle5]

I was hopeful someone might have a suggestion. The battle continues...

 

[01ssreda4]

BCM must be correctly vin coded or it will trigger vats. When my battery was doing similar i hit the dome light override button by the headlight switch and it magically stopped going dead.

 

[rayfinkle5]

BCM must be correctly vin coded or it will trigger vats. When my battery was doing similar i hit the dome light override button by the headlight switch and it magically stopped going dead.

No magic for me unfortunately.

 

[ISU-152]

No magic for me unfortunately.

Einhorn can you repeat your steps again?

Did anyone check alternator/fuses/relays before the new bcm