GM Service Manual Online
For 1990-2009 cars only

Important: The power door locks are controlled by the body control module (BCM). The BCM allows the door locks to operate for 10 minutes after the ignition is turned off and both of the doors remain closed. The BCM also allows the door locks to operate for 35 seconds after exiting the vehicle and closing the doors. The door locks are enabled whenever either door is open unless the ignition key is in the ignition and the lockout prevention feature is enabled. Refer to Retained Accessory Power (RAP) Circuit Description in Retained Accessory Power for a complete understanding of RAP operation.

Both door lock actuators lock or unlock when either door lock switch is pressed. The locks are operated by reversible actuators. The door lock switches operate the actuators by applying a ground input signal to the BCM. The BCM then commands the actuators to lock or unlock. When the right door lock switch or the left door lock switch is moved to the lock position, ground is applied to the BCM lock input through circuit 780. The BCM then applies battery voltage to both actuators through circuit 295. The actuators are grounded by the BCM through circuit 694 and through circuit 1663. When the right door lock switch or the left door lock switch is moved to the unlock position, ground is applied to the BCM unlock input through circuit 781. The BCM applies battery voltage to the actuators through circuit 694 and through circuit 1663. Both of the actuators are grounded by the BCM through circuit 295. The ground is supplied to the BCM by G200 through circuit 650.

Door Lock Feature Customization

The body control module  (BCM) can be programmed to customize the power door lock operation. The two programmable functions are described below.

Last Door Closed Locking

The last door closed locking feature allows delayed door locking on all vehicles equipped with power door locks. This feature assures that all vehicle doors are locked after the driver and all passengers have exited the vehicle. When the driver door lock switch is pressed, an audible warning tone sounds three times to indicate that the last door closed locking function is initiated. The doors lock automatically three seconds after both doors are closed. Pressing the door lock switch to the unlock position after the warning tones cancels the last door closed locking function. Pressing the door lock switch to the lock position twice locks the doors immediately. The last door closed locking function does not work if the ignition key is in the ignition switch and the lockout prevention feature is enabled. The last door closed locking feature is disabled from the factory. To enable the last door closed locking feature, refer to Feature Customization in Theft Deterrent.

Lockout Prevention

The lockout prevention feature prevents the driver from locking the ignition key in the vehicle. The power door locks are disabled with the ignition key in the ignition and a door open. When the door lock switch is pressed with a door open an audible warning sounds five times as a reminder to remove the ignition key. The lockout prevention feature is disabled from the factory. To enable the lockout prevention feature, refer to Feature Customization in Theft Deterrent.