The power door lock system consists of the following components:

The power door lock system can be controlled by any of the following:

The front power door lock switches are integral components of the driver door module (DDS) and passenger door module (PDS). The switches are 2 position normally open rocker switches. When placed in either the lock or unlock positions, the switches provide a direct input to the DDS or PDS. The DDS or PDS monitors these inputs and sends a LAN message indicating a change in the switch's respective position. Modules which activate the power door lock motors receive the GMLAN message and activate the motor in the appropriate direction to lock or unlock the vehicle's doors and liftgate. The rear door lock switch provides a lock and unlock signal to the body control module (BCM). The BCM upon receipt of a lock or unlock signal will control the rear door lock/unlock relay and also send a GMLAN message to the DDS and PDS to perform the appropriate function.

The modules which activate the power lock motors are:

The DDS and PDS are directly connected to the respective door lock actuator through the door lock motor lock and unlock circuits. Once a door lock or unlock request has been received, the module will supply battery voltage to one side of the actuator and ground the other causing the doors to lock or unlock.

The rear passenger and endgate doors are controlled by the BCM through the rear door lock/unlock relay which is incorporated onto the printed circuit board in the LH BEC. The BCM controls the unlock relay by providing ground to energize the coil and controls the lock relay by providing battery voltage to energize the relay coil. The energized the relay and allows voltage to be applied to either the door lock motor lock or unlock circuits. Since the other side of the door lock actuator is connected to the normally closed contacts of the opposing relay to ground, the doors lock or unlock.

The automatic door lock feature can be programmed to control the door lock system. The automatic door lock feature is factory programmed to have all doors lock and unlock.

When the automatic door lock feature is programmed to control the door lock system, the driver door switch (DDS), passenger door switch (PDS) and body control module (BCM) will lock the vehicle doors if the following inputs are true:

This automatic door lock function will only occur once per ignition cycle unless, a door jamb switch input changes state to active and back to inactive. Then the DDS, PDS and BCM will lock all doors again.

Once the automatic door lock feature has locked the doors, the BCM will then unlock all the doors when the transmission is shifted into PARK.

This feature prevents the locking of the driver door if the ignition key is left in the ignition lock cylinder. If a lock function occurs from any door lock switch and the body control module (BCM) senses an active state on either the left front door latch signal, secondary door latch switch signal and/or the liftgate ajar switch signal circuits and the key in ignition switch signal circuit is in the YES state, the BCM, driver door switch (DDS) and passenger door switch (PDS) will lock the doors and then the DDS will unlock the driver door.

With any door open and a door lock switch is activated in the lock position, the driver door switch (DDS), passenger door switch (PDS) and the body control module (BCM) will go into a lock pending state. The BCM will also give 3 audible chimes. When the door is closed, the DDS, PDS and the BCM will lock the doors after approximately 5 seconds. This feature can be overridden by activating the door lock switch a second time and the doors will lock even with a door open.