The power door lock system consists of the following components:

Activation of the driver or front passenger door lock switch to the LOCK position provides an input signal to the BCM, which in turn provides an output (ground) signal to the coil of the door lock relay. The door lock relay energizes, supplying B+ to the door lock actuators locking all the doors.

The unlock operation is similar to the lock operation except that polarity is reversed.

Activation of the driver or front passenger door lock switch to the UNLOCK position provides an input signal to the BCM, which in turn provides the following outputs:

Automatic door locking is performed by the BCM when the key is in the ignition RUN position, the vehicle has been shifted out of Park and all the doors are closed. With the ignition switch in the RUN position, a B+ Run/Crank input signal is sent to the BCM from the ignition switch. When the transmission is shifted out of Park, the Out of Park input to the BCM is grounded through the automatic transmission shift lock control switch. When the BCM detects these inputs, activates the door lock actuators as described in Door Lock Operation.

When the transmission is shifted into the PARK position, ground is removed from the Out of Park input to the BCM. When the BCM detects that the ground has been removed from its input, it activates the door lock actuators as described in Door Unlock Operation.