Door Lock and Unlock Operation

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 lock or unlock relay(s). The relay will supply voltage to the door lock actuator lock or unlock control circuits to one side of the lock actuator. Since the opposing side of the lock actuators are 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 appropriately.

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