If this has been discussed before I apologize. I have a 2001 2500HD, 8.1L, Allison. There is a drain on my battery I cannot figure out. I hooked a multimeter on the negative side of the battery and have a draw of .03 amps and in 3-4 days the battery will be down to 10.9 volts. The draw is the TBC fuse. The battery is fairly new and does very good on a load test.

I am stumped

 

The TBC fuse supplies direct battery voltage to the BCM, headlamp & panel dimmer switches, and remote door lock receiver (if equipped with keyless entry).

Are there any issues with the interior? Something such as the door ajar indicator light staying on even with all the doors closed? What about displays on the radio/HVAC panel?

 

There are no lights on anywhere, nothing on the dash or radio. What I don't understand is 30 milliamps is supposedly a good reading. If so why is the battery going dead, is something coming on when I am not watching the meter?

 

Same question was asked recently here:
https://chevroletforum.com/forum/upl...-101952/page2/

30 mA will not kill a battery unless it is in very bad shape.

Maybe a faulty door switch is triggering the interior lights when you're not there.

 

It’s normal for modules to continue communicating for a few hours after key off, but after sitting overnight, the modules should all be in a sleep mode. How long did you monitor the draw?

Sometimes glitches can cause modules not to be shutting down when they should be. If the BCM or door lock receiver aren’t going to sleep for some reason, you might be able to correct it by doing a “hard reset.” Disconnect both battery cables and use a clamp, bolt or jumper wire to connect them together for a 1/2 hour - this allows current flow and will discharge the backup batteries in the modules which will clear the adaptive memory.

Expect a few drive ability issues when you first drive it because this will also clear the adaptive memory of the PCM.

 

Thanks for your reply, I will look into that

 

Thanks Gumby22. I originally left the meter hooked up for 4 days, on Friday I disconnected a backup camera monitor. After everything went to sleep my meter reads .01 amps and the battery was 12.73 volts. Today still .01 and 12.64 volts.

 

Sorry for the long wait. Starting with a fully charged battery and giving everything time to go to sleep I have a .2 millivolt reading on the 10 amp TBC fuse or 26 milliamps. After 7 days the battery is down to 12.52 volts, is this normal?

 

That is a healthy voltage. You shouldn't have any trouble starting up.