Battery Rundown Protection
WARNING: This page is about a different car, the 2000 GMC Yukon, 2000 Chevrolet Tahoe, 2000 Chevrolet Pickup, and 2000 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
BCM helps to prevent inadvertent battery rundown from situations such as courtesy lights left on. BCM will turn off courtesy light circuit after ignition has been off for 20 minutes and no light request input has been received.