Burgermeisteradam

I'm working on a 2003 impala with a parasitic draw that comes and goes from 2200 miliamps down to 50 and back up. The draw seems to be isolated to the trk/roof/brp fuse. Interestingly when the trunk is open the draw is gone. When the rear view mirror is unplugged the draw is gone. When it's all connected and trunk closed I can hear the speakers kick static on and off with the draw. Have been working on this car for 3 weeks and still can't find it. I disconnected the trunk switch and latch mechanism and it doesn't make the draw go away only with the trunk open and everything connected does it behave as it should. That or with the rear view mirror unplugged. Any help would be appreciated thanks much

Burgermeisteradam

Also I have tried a different Bcm in the car with no success

tech2

a55bruce

When you have the trunk open, is the trunk light ON? Do you get the "trunk open" warning message on the instrument panel ? The trk/roof/brp fuse supplies power to the interior lights, so every time you open a door or click the remote the lights will come on showing up as a power draw. Is the "Battery Rundown Protection relay" a plug-in relay? Maybe it's sticking ON.

Burgermeisteradam

The brp relay is good and when the trunk is open the trunk light comes on and then times out and once it times out the draw goes down to 6miliamps and stays there and as soon as I close the trunk the draw is back. Another thing I forgot to mention is that I locked myself in the car and was listening for clicking relays with the multimeter in the line and when it was drawing the speakers were putting out a quiet static then when the draw dropped the speakers stopped hissing. Then a few moments later they would start up again. I disconnected the radio but that only took about half of the draw away. I was thinking bcm because of this but I have no idea what else would cause this. I will look into the vcim though. Is there anyway of testing this module to see that it's functioning properly?

Burgermeisteradam

For now what I have done to "fix" the problem is I disconnected the blue power wire from the rear view mirror that brings power to the reading lamps that are built in. No on star just reading lamps and auto dimming feature are included in this mirror. The reading lights don't work but at least the car doesn't go dead over night. I would like to find and fix the real root problem here before giving it back to the customer

tech2

have you tried the iatn? International Automotive Technicians Network

Frank3

Are you getting any codes on the car? My 2001 Impala would intermittently kill the battery as well. I had a hard time figuring it out, so I brought it to the dealer (they couldn't figure it out either) and "adjusted some wiring and reseated the horn relay". The dealer did provide me will all the codes they scanned. When I looked them up, they were something like (working from memory) horn circuit connected to ground and something pretty much the same with the headlights. I cracked open the service manual when I got those codes to see what was in common. It was the BCM. You see when my wife locks the car she uses the remote and then as the car locks the horn chirps and the headlights flash. I went to the dealer with the previous invoice, and told them I wanted the BCM replaced. They asked why would you want that done? I told them because that's where the error codes I have intersect. Next question? Where did you get those error codes? - Off of the invoice you gave my wife when she brought it in 2 days ago for this problem.

The battery drain problem went away after the BCM was replaced.