Door Lock and Unlock Operation

WARNING: This page is about a different car, the 2016 GMC Acadia, 2016 Chevrolet Traverse, and 2016 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.

When a door lock switch is activated in the lock or unlock position the body control module (BCM) will receive a voltage signal on either the door lock switch lock or unlock signal circuits.

The BCM, upon receipt of a lock switch lock or unlock signal, will switch the appropriate lock relay control circuit(s) to battery positive voltage. This will energize the appropriate relay(s). The relay will supply voltage to the door lock actuator lock or unlock control circuits. Since the opposit side of the lock actuator is connected to ground through the other lock actuator control circuit and the normally closed contacts of the lock or unlock relay, the doors and liftgate will then lock or unlock as commanded.

Three relays are used to operate the lock. Driver door unlock, passenger door unlock and all door lock. The driver door lock actuator is isolated so it can be unlocked by itself using the keyless entry transmitter.