Power Locks: Description and Operation

Power Door Locks Description and Operation

Door Lock System Components

The power door lock system consists of the following components:

* Driver door lock switch

* Passenger door lock switch

* Central door lock switch

* Child door lockout switch

* Door lock actuators in each of the doors

* Body control module (BCM)

* Underhood fuse block

Door Lock System Controls

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

* A door lock switch LOCK or UNLOCK activation

* A mechanical key cylinder lock/unlock

* A keyless entry transmitter activation

* An automatic door lock activation

* An automatic door unlock activation

Door Lock Operation

When a door lock switch is activated in the lock or unlock position the body control module (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 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 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

Child Door Lockout Operation

The operator has the option to disable the interior rear door handles to prevent the unauthorized opening of the rear door doors while still retaining normal rear exterior door handle functions. The rear door latches contain switches that are open when the rear doors are open and closed when the rear doors are closed. When the child door lockout switch is pressed, the BCM will confirm that the rear doors are closed, if the rear doors are closed the BCM will then disable the interior rear door handles and will command the child lockout indicator to illuminate. The rear door plungers will still function normally by pressing the central door lock switch but the child lockout latches will disable the interior rear door handles. Pressing the child lockout switch again will signal a command to the BCM restore normal interior rear door handle functions and the turn off the child lockout indicator.

If the child lockout indicator flashes while trying to lockout the rear door handles means one or both rear doors are open or ajar or there is a fault detected in the child lockout system and one or both interior rear door handles will not be disabled.