00 GC BCM reprogram?

Can the BCM be reprogrammed if its suspected to be bad? I have no low beams. Or do I buy another and is it plug and play?

Not sure about reprogramming but I don't thinks so. If you get a different BCM you need to get one with the matching numbers on it. You may have to get it prgrammed to change the odometer reading which is stored in the bcm. Check all other possiblities before changing bcm.