Power Locks: Description and Operation

When a door lock switch is activated in the power door lock system, all of the doors lock or unlock in unison. Each lock can also be operated manually from the locking knob. The locks are operated by reversible actuators that receive voltage from the Body Control Module (MALL). The module turns on the actuators by applying voltage to one terminal and ground to the other terminal.

When a door lock switch is moved to the LOCK position, it completes the circuit to the Body Control Module (MALL). The MALL Module then applies voltage and ground to the door lock actuators. The actuator in each door runs to operate the door locks.

A similar action occurs when a door lock switch is moved to the UNLOCK position. The voltage polarity to the actuators reverses causing the actuators run in the opposite direction and unlock the doors.

The door lock switches are usually closed for just a moment. If they are held closed, an electronic circuit breaker in each actuator opens to protect against damage. The circuit breakers have Positive Temperature Coefficients (PTC) which reset automatically when voltage is removed from the actuator.

Automatic Door Locks
The automatic door locks are controlled by the Remote Function Actuator (RFA) Module. The RFA Module receives a signal from the Park/Neutral Position Switch stating whether the gear selector is in PARK or not. When the LH door is closed, if the vehicle is in RUN and the gear selector is shifted out of PARK, the RFA Module applies ground to the Body Control Module (MALL), which locks the doors. If programmed to do so, the RFA Module unlocks the doors when the gear selector is put back in to PARK.

Automatic Door Lock Programming
The automatic door lock function provides for four selectable settings, as follows:
1. No automatic door lock or unlock.
2. Automatic all door lock when the gear selector moves out of PARK. No automatic door unlock.
3. Automatic all door lock when the gear selector moves out of PARK. Automatic driver door unlock when the gear selector moves into PARK.
4. Automatic all door lock when the gear selector moves out of PARK. Automatic all door unlock when the gear selector moves into PARK.

Refer to Remote Keyless Entry for automatic door lock programming procedures. Keyless Entry