Battery Rundown Protection
WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Chevrolet Cavalier, 2001 Pontiac Sunfire, and 2001 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
Body Control Module (BCM) helps to prevent inadvertent battery rundown from courtesy lights left on. BCM monitors current draw on courtesy light circuit and will interrupt power to courtesy lights to minimize battery drain. When ignition is turned off, a time-out period of 20 minutes begins. After 20 minutes, inadvertent output is turned off. When BCM receives a wake up signal, it will turn output back on and reset time-out period.