GM Service Manual Online
For 1990-2009 cars only

Door Lock System Components

The power door lock system consists of the following components:

    • Central door lock switch--Provides a switched voltage signal to the rear fuse block for both lock and unlock switch activations.
    • Door lock relay--Located behind a panel near the rear wheel well and controls the crash unlock.
    • Door unlock relay--Located behind a panel near the rear wheel well and controls the crash unlock.
    • Rear fuse block--Class 2 module which requires programming when replaced.
    • Reversible door lock actuators in each of the doors.
    • F10 fuse--Located in the underhood fuse block, supplies power to the relays.

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
    • Delayed locking command
    • Automatic door lock command
    • Lockout prevention command
    • An air bag deployment

Door Lock and Unlock Operation

When a door lock switch is activated in the lock or unlock position the rear fuse blockwill receive a voltage signal on either the door lock switch lock or unlock signal circuits.

The rear fuse block, upon receipt of a lock switch lock or unlock signal, 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 rear fuse block, the doors and liftgate will then lock or unlock appropriately.

Automatic Door Lock Operation

The rear fuse block 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 rear fuse block will then unlock the doors when the ignition is placed in the OFF position.

Delayed Locking Operation

With any door open and a door lock switch is activated in the lock position, the rear fuse block will give three audible chimes. When the door is closed, the rear fuse block will cycle the internal door lock relay to lock the doors after approximately five 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.

Lockout Prevention Operation

The rear fuse block 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.

Unlock After Crash

This feature will unlock all of the vehicle doors 15 seconds after an air bag deployment.