Circuit/System Description

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

When the body control module (BCM) detects a transition of either of the door lock switches to the LOCK position, it switches the door lock actuator lock control circuit to voltage. Since the door lock actuator lock control circuit is at ground potential within the BCM, the door lock actuators transitions to the LOCK position and when the BCM detects a transition of either of the door lock switches to the UNLOCK position, it switches the door lock actuator unlock control circuit to voltage. Since the door lock actuator unlock control circuit is at ground potential within the BCM, the door lock actuators transitions to the UNLOCK position.

The driver door lock actuator unlock control circuit is a dedicated control circuit used only for the driver door lock actuator motor. This is done so that the driver door may be unlocked by itself using a keyless entry transmitter or an automatic door unlock function, if programmed.