2003 Chevy Impala BCM Issues

Ok here is a strange issue again. The cars battery voltage spikes, the battery light comes on, the headlights and the reverse lights flicker on and off and you can hear a clicking noise coming from the dashboard. We have found the only way to rid this is to keep disconnecting the battery when parked. Another thing we discovered was turning the air conditioner on the floor setting and leaving the car running until the inside cooled down. This would stop all of the above from happening. My daughter's bf knows about cars and insists that it is the BCM. I know this needs to be programmed at a dealer but does it need to be purchased at a dealer? If not where is the best place to get one? Also what is your opinion on the BCM truly being the issue?

BF's know best.....even without any testing or diagnosis....

with the battery disconnected, remove the 3 connectors from the BCM , Squirt all the contacts with electrical contact cleaner, not to be confused with electrical motor cleaner. Let dry and plug in again. Sounds plausible that it could be the BCM. You can get BCMs from junk yards. With a techII scan tool they need to be linked up to the PCM (car computer). You will have to remove the panel that has the coutesey light, the bcm is up by the brake pedal.

Problem with getting BCM's from junkyards is, they are not programmed to your particular vehicle, they have to be programmed with the options that are in your vehicle.......depending on the year, in some cases you can't do it, because other modules won't recognize the BCM if it has a different VIN # stored in it....in some cases, once programmed, they can't be reprogrammed.....

Once GM went to the GDS system, the old trick of "taking a known good module" out of another vehicle and trying it in a car with a problem, will not work anymore......it will not be recognized by the other modules in the car, and actually create more problems, especially communication problems....

BF's know best.....even without any testing or diagnosis....


:) Ok not to sound blonde or anything...but are you being funny or do you think he is right? lol