Door Lock Operation
WARNING: This page is about a different car, the 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, 2001 Chevrolet Monte Carlo, and 2001 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
When BCM detects a transition of either of the door lock switches to LOCK position, it switches door lock actuator lock control circuit to voltage. Since door lock actuator unlock control circuits are at ground potential within BCM, door lock actuator motors transition to LOCK position.