GM Service Manual Online
For 1990-2009 cars only

Locking

Setting a power door lock switch to the LOCK position provides an input signal to the body control module (PZM) on one of the following circuits:

    • CKT 780 (RED/BLK)
    • CKT 244 (LT BLU)

The switch grounds a terminal on the PZM through the following circuits:

    • CKT 51 (BLK/WHT)
    • CKT 151 (BLK/WHT)

The PZM provides an output on CKT 195 (LT BLU). This condition grounds the lock coil of the power door lock relay. With voltage applied to the lock coil, the power door lock relay energizes. This condition provides power from the CONVENIENCE fuse to the door lock actuators through the closed relay contacts and CKT 295 (GRY). The door lock actuators lock the doors because they are grounded. The right front and the rear (on the four-door models) door lock actuators are grounded at G401 through the following components:

    • CKT 294 (TAN)
    • CKT 1250 (BLK)
    • The UNLOCK relay contacts

The left front door lock actuator is grounded at G401 through the following components:

    • CKT 694 (TAN)
    • CKT 1250 (BLK)
    • The left front door UNLOCK relay

Unlocking

The unlocking operation is similar to the locking operation except that the polarity of the voltage applied to the door lock actuators is reversed. The completed circuit causes the actuators to run in the opposite direction, which unlocks the doors.

Setting a front door lock switch to the UNLOCK position provides an input signal to the PZM on the following circuits:

    • CKT 781 (ORN/BLK)
    • CKT 245 (DK BLU)

The switch grounds a terminal on the PZM to ground the following circuits:

    • CKT 151 (BLK/WHT)
    • CKT 51 (BLK/WHT)

The PZM provides two output signals that accomplish the unlocking function.

On one circuit, the PZM provides an output on CKT 194 (WHT) that grounds the unlock coil of the power door lock relay. The unlock relay contacts close, providing power from the CONVENIENCE fuse to the right front and the rear (on the four-door models) door lock actuators through the closed relay contacts and CKT 294 (TAN).

The voltage to unlock the left front door lock actuator is applied through the left front door unlock relay. When unlocking, the PZM provides an output on CKT 1391 (LT GRN) that grounds the coil of the left front door unlock relay. Voltage on CKT 2040 (ORN) energizes the relay coil. The CONVENIENCE fuse supplies the power to the front door lock actuator through the following components:

    • CKT 2040 (ORN)
    • The closed relay contacts
    • CKT 694 (TAN)

All of the door lock actuators run because the actuators are grounded through the following components:

    • CKT 295 (GRY)
    • The lock relay contacts of the door lock relay
    • CKT 1250 (BLK)

Central Door Unlocking

The left front door and right front door lock cylinder switch provides an input to the PZM. This input is CKT 262 (LT GRN) for the left front door. The input is CKT 265 (LT GRN) for the right front door. The PZM uses these inputs in order to control the central door unlock feature.

Anti-Lockout

The PZM disables the power door locks under the following conditions:

    • The PZM receives a key in the ignition input signal.
    • The PZM receives a left front door open input signal.

In order to override the anti-lockout feature, hold the power door lock switch in the lock position for 3 seconds or more.

Door Lock/Unlock Functions

The PZM locks and unlocks all of the doors by the following methods:

    • Door lock/unlock switch activation
    • Pressing the door lock or unlock switch on the remote function actuator
    • Auto door lock function enabled
    • Central door unlocking enabled

Programming Automatic Door Locks

The vehicle's ignition must be in RUN. To begin programming, press and hold the SKIP INFO and NO INFO RESET buttons at the same time in order to display the following prompts:

    • DOORS LOCK IN GEAR: All doors automatically lock when shifted out of PARK (P). No automatic door unlock.
    • DRIVR UNLOCK IN PARK: All doors automatically lock when shifted out of PARK (P). Only the driver's door automatically unlocks when shifted into PARK (P).
    • DRIVR UNLOCK KEY OFF: All doors automatically lock when shifted out of PARK (P). Only the driver's door automatically unlocks when the ignition key is turned to OFF.
    • DOORS UNLOCK IN PARK: All doors automatically lock when shifted out of PARK (P) and unlock when shifting into PARK (P).
        DOORS UNLOCK KEY OFF: All doors automatically lock when shifted out of PARK (P). All doors automatically unlock when the ignition key is turned to OFF.

A YES or NO response must be made after each prompt is displayed in order to continue on to the next prompt or personalization feature. Press the YES TRIP RESET button to choose yes, press the NO INFO RESET button to choose no or press the SKIP INFO button to skip to the next personalization feature.

FEATURE ON appears when a yes response is made and FEATURE OFF appears with a no response.

If a no response is made after the DOORS LOCK IN GEAR prompt is displayed, FEATURE OFF will appear. The automatic door locking system has been disabled and no other door lock messages will be displayed. LIGHTS FLSH AT UNLOCK, which is the next available personalization feature to display, will appear next.

If a yes response is made after the DOORS LOCK IN GEAR prompt is displayed, FEATURE ON appears. The automatic door locking system is enabled and allows the DRIVR UNLOCK IN PARK prompt to appear. Choosing this prompt advances you to LGHTS FLSH AT UNLOCK whereas a no response will display the DRIVR UNLOCK KEY OFF prompt.

If DRIVR UNLOCK KEY OFF is chosen, FEATURE ON appears. Advance to the LGHTS FLSH AT UNLOCK prompt. FEATURE OFF appears as well as the next prompt- DOORS UNLOCK IN PARK if this prompt isn't chosen. FEATURE ON appears if this prompt is chosen. If a no response was made, DOORS UNLOCK KEY OFF will appear. At this point, a yes or no response automatically brings up the LGHTS FLSH AT UNLOCK feature.