GM Service Manual Online
For 1990-2009 cars only

All Door Unlock

The BCM unlocks all doors when pressing unlock once on either door lock switch. Note: the BCM does not unlock the doors when the content theft deterrent system (RPO UA6) is armed.

Pressing unlock on either door lock switch sends a ground signal to the BCM through circuit 194. This action cause the BCM to apply voltage in circuits 694 and  294 for 350 (+/- 35) ms, energizing all door lock actuators and unlocking all vehicle doors. The BCM grounds the door lock actuators through circuit 295.

All Door Lock

    • The BCM locks all doors when pressing lock once on either door lock switch with all doors closed.
    • The BCM delays door locking when the driver's door is open with the key removed from the ignition switch, thus enabling the last door closed locking feature if the locking control mode is in mode 3 or 4. A first press of lock on a door lock switch initiates this feature. This causes the BCM to sound the chime 3 times, indicating last door closed locking is active. Five seconds after all doors are closed, the BCM locks all doors. Pressing lock twice on a door lock switch bypasses the last door closed locking feature, thus the BCM locks all doors immediately with a door still open.
    • The BCM does not lock the doors when the driver's door is open and the key is fully inserted in the ignition switch, thus enabling the lockout prevention feature.

Pressing lock on either door lock switch sends a ground signal to the BCM through circuit 195. When the BCM deems appropriate to lock the doors (based on last door closed locking and lockout prevention features) the BCM applies voltage to circuit 295 for 350 (+/- 35) ms, energizing all door lock actuator motors and locking all vehicle doors. The BCM grounds the door lock actuators through circuit 294.

Sliding Door Delayed Locking

The BCM initiates the sliding door delay locking feature when pressing lock on either door lock with a sliding door open, on one of these conditions is met:

    • The ignition switch in ACC or RUN position.
    • The ignition switch in LOCK or OFF position and the last door closed locking feature is disabled. Refer to Automatic Door Lock System Description .
    • The ignition switch in LOCK or OFF position and the lockout prevention override feature is enabled. Refer to Automatic Door Lock System Description .

In addition, the BCM initiates the sliding door delay locking feature when the shift out of PARK lock feature is active with a sliding door open.

When the sliding door delayed locking feature is initiated (see criteria above), the BCM locks all doors three seconds after closing sliding door(s). The BCM to apply voltage in circuit 295 for 350 (+/- 35) ms, energizing all door lock actuators and locking all vehicle doors. The BCM grounds the door lock actuators through circuit 294.

Sliding Door Delayed Locking Override

The BCM locks all doors when pressing lock on either door lock switch or keyless entry transmitter during the three second delay period. This action overrides the sliding door delay locking feature. However, the BCM will not lock doors if the lockout prevention is active. Refer to Automatic Door Lock System Description .

If a sliding door was open at the time the BCM locks all doors (override feature activated), the BCM initiates the sliding door delay locking feature after closing sliding door(s).

Sliding Door Delayed Locking Cancellation

The BCM cancels the sliding door delay locking feature when pressing unlock on either door lock switch or keyless entry transmitter.

When opening a sliding door during the three second delay period, the BCM cancels the sliding door delay locking feature and waits for sliding door(s) to close again. When closing sliding door(s), the BCM re-initiates the sliding door delay locking feature.

Key Cylinder Unlock (RPO UA6)

When using the LF, RF or liftgate door key cylinder, the BCM unlocks all vehicle doors while holding the key in the unlock position for 1 second.

Unlocking the door using the key lock cylinder sends a ground signal to the BCM through circuit 781. Holding the key in the unlock position for one second causes the BCM to apply voltage in circuits 694 and 294 for 350 (+/- 35) ms, energizing all door actuators and unlocking all vehicle doors.

Key Cylinder Lock (RPO UA6)

When using the LF, RF or liftgate door key cylinder, the BCM locks all vehicle doors while holding the key in the lock position for 1 second.

Locking the door using the key lock cylinder sends a ground signal to the BCM through circuit 780. Holding the key in the lock position for one second causes the BCM to apply voltage in circuits 295 for 350 (+/- 35) ms, energizing all door actuators and locking all vehicle doors.

Courtesy Lights

Illuminated Entry

The BCM turns on the courtesy lights when unlocking the LF, RF, or liftgate door using door cylinder lock (BCM type 4 only). Refer to Interior Lights Circuit Description for more information.

Delayed Illumination

The delayed illumination feature is canceled when pressing lock on a door lock switch or a keyless entry transmitter. Refer to Interior Lights Circuit Description for more information.