Door Lock and Unlock Motor Operation

The power door lock motors are contained within each door latch assembly. The DDM and PDM each supply battery voltage and ground through there respective door lock and unlock actuator control circuits to its associated door latch assembly motor. The power door lock motors are reversible and are responsible for both the locking and unlocking functions of the associated door. When the door control modules receive a locking request, the modules will respond by momentarily applying voltage to the door lock actuator lock control circuit, and ground to the door lock actuator unlock control circuit. To unlock the front doors, the door control modules reverse the polarity by momentarily applying voltage to the door lock actuator unlock control circuit, and ground to the door lock actuator lock control circuit.

The left and right rear power door locks are controlled by the body control module (BCM). The BCM, upon receipt of a lock or unlock signal, will control the rear door lock or unlock relay, activating the power door lock motors in the appropriate direction to lock or unlock the rear doors. When the BCM receives a locking request, the BCM energizes the lock relay by applying voltage to the lock relay coil via the rear door lock actuator lock control circuit. With the lock relay energized, battery voltage flows through the relay controlled output circuit to both rear door lock motors causing both rear doors to lock. Ground for both rear door lock motors is supplied by the rear door unlock relay controlled output circuit. With the rear door unlock relay in a nonenergized state, the switch contacts are in a normally closed state with a path to a ground. For a rear door unlock function, the BCM energizes the unlock relay by applying ground to the unlock relay coil via the rear door lock actuator unlock control circuit. The rear door unlock relay coil is supplied with battery voltage at all times. With the unlock relay energized, battery voltage flows through the relay controlled output circuit to both rear door lock motors causing both rear doors to unlock. Ground for both rear door unlock motors is supplied by the rear door lock relay controlled output circuit. With the rear door lock relay in a nonenergized state, the switch contacts are in a normally closed state with a path to a ground.