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Power Door Locks Description and Operation

Power Door Locks Description and Operation

Door Lock System Components

The power door lock system consists of the following components:


Door lock switch, located in the hazard lamp switch in the center of the instrument panel

Body Control Module (BCM)

Driver door latch

Passenger door latch

Left rear door latch

Right rear door latch


Door Lock System Controls

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


Power door lock switch activation

Keyless entry lock or unlock command

A door lock cylinder switch Unlock actuation

Delayed locking command

Automatic door lock command


Door Lock and Unlock Operation

When a door lock switch is activated in the lock or unlock position the BCM will receive a ground 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 supply battery voltage to the door lock actuator lock or unlock control circuits. Since the opposite side of the lock actuator is connected to ground through the other lock actuator control circuit, the doors, fuel filler door and liftgate will then lock or unlock as commanded.

The following three circuits are used to operate the lock:


Driver door unlock

Passenger door unlock

All door lock


The driver door lock actuator is isolated so it can be unlocked by itself using the keyless entry transmitter.

Automatic Door Lock Operation

This BCM-controlled feature can be personalized to driver preference.

The BCM will automatically lock the vehicle doors if the following conditions exist:


All vehicles doors are closed.

The ignition is in the ON position

The vehicle is shifted out of Park.


The BCM will then unlock the doors when vehicle is shifted back into Park.

Power Door Lock Deadbolt Operation

Vehicles equipped with the deadbolt feature include an additional reversible deadbolt motor contained within each door latch assembly. Each deadbolt motor is wired to the BCM through 2 control circuits; the door lock deadbolt control circuit and the door lock actuator unlock control circuit. To deadbolt a door, the door locks are activated by momentarily applying voltage to the door lock deadbolt control circuits, and ground to the door lock actuator unlock control circuits. Ground to the deadbolt actuators is provided through the door lock actuator unlock control circuits. Once the doors are deadbolted, the mechanical lock/unlock linkage within the door lock actuator is physically disconnected so that the door can not be manually unlocked. If the content theft feature is armed at the same time, the interior door lock switches will not operate the locks.

To undeadbolt the doors, the BCM unlocks the doors by momentarily applying ground to the deadbolt motor unlock control circuit. This energizes the rear door unlock relay coil causing voltage to flow through the switch contacts to the door lock and deadbolt motors. Ground for both motors is supplied through the door lock motor lock circuit through the normally closed contacts of the lock relay to ground.

By performing the following actions, the doors can be locked and deadbolted or unlocked using the keyless entry transmitter:


Press the keyless entry transmitter lock button once to lock all doors, then press a second time within 3 seconds to deadbolt all doors.

Press the keyless entry transmitter unlock button once to unlock the driver door, then press a second time within 3 seconds to unlock all passenger doors.


Delayed Locking Operation

With any door open and a door lock switch is activated in the lock position, the BCM will give three audible chimes. When the door is closed, the BCM will cycle the internal door lock relay to lock the doors after approximately five seconds. The function can be overridden by activating the door lock switch a second time. The doors then lock even if a door is open.

Lockout Prevention Operation

The BCM will lock all doors and unlock the driver door with a door lock switch lock activation if a vehicle door is open and the ignition key is fully inserted in the ignition. The lockout prevention feature can be overridden if a lock command is received from the keyless entry system.