GM 15918137 Lock Actuator

The power door lock system operates the door lock actuators in each door, consisting of switches, actuators, Body Control Module (BCM), and associated wiring. Diagnosis typically involves checking the wiring connections and actuators for minor faults that can be easily repaired. The system is operated by bi-directional solenoids located in the doors, with lock switches having two positions: Lock and Unlock. These switches send a signal to the BCM, which then sends a signal to the door lock solenoids. It is important to check the circuit protection first, as some vehicles use a combination of circuit breakers and fuses. If no voltage is present at the switches, the wiring between the fuse panel and the switches should be checked for shorts and opens. If voltage is present, the switch should be tested for continuity and replaced if there is none. If it has continuity, check the wiring between the switch and the solenoid. If all but one lock solenoids operate, the trim panel should be removed from the affected door to check for voltage at the solenoid while the lock switch is operated. If the inoperative solenoid is not receiving voltage, an open or short in the wire between the lock solenoid and the relay should be checked.