Colorado Battery Drain

[n9cv]

2005 Colorado Z71 WT with I-5. - Manufacture date 9/7/2004

 

This truck has a 220 ma. battery drain that discharges the battery down to dead over a week or so. I have traced the drain to fuse 37 which is the front 4 way flasher and turn signal bulbs. The bulb circuit goes through the BCM. Removing both bulbs does not change the drain. The drain appears to be in the BCM itself. Removing and reinserting F33 which resets the BCM removes 200 ma. of the drain leaving 20 ma. which I feel is probably the normal for the BCM. Opening and closing the door starts the drain again. The drain never goes away. I waited one time for 38 hours with the keys removed from the ignition and still had the 220 ma. drain. This is a work truck and does not have electric windows or electric locks. I know next to nothing about the BCM but I feel this is a BCM software problem.

 

Are there levels of code for the BCM?

Could this possibly have been fixed in later Colorados and all I need is a BCM code update?

How do you check the current code level or update the code level if necessary?

 

I checked with a local Chevy dealer are got no where.

 

Thanks for any input or ideas.