Power Door Lock Actuator: Testing and Inspection

Before you proceed with this diagnosis, confirm proper power lock switch, Central Timer Module (CTM), and power lock switch output circuit operation. Remember, the CTM circuitry controls the output to each of the power lock motors.
1. Check each power lock motor for correct operation while moving the power lock switch to both the Lock and Unlock positions. If all of the power lock motors are inoperative, go to Step 2. If one power lock motor is inoperative, go to Step 3.
2. If all of the power lock motors are inoperative, the problem may be caused by one shorted motor. Disconnecting a shorted power lock motor from the power lock circuit will allow the good power lock motor to operate. Disconnect the wire harness connector from each power lock motor, one at a time, and recheck both the lock and unlock functions by operating the power lock switch. If all of the power lock motors are still inoperative after the above test, check for a short or open circuit between the power lock motors and the CTM. If disconnecting one power lock motor causes the other motors to become functional, go to Step 3 to test the disconnected motor.
3. Once it has been determined which power lock motor is inoperative, that motor can be tested as follows. Disconnect the wire harness connector from the inoperative power lock motor. Apply 12 volts to the lock and unlock driver circuit cavities of the power lock motor pigtail wire connector to check its operation in one direction. Reverse the polarity to check the motor operation in the opposite direction. If OK, repair the shorted or open lock or unlock driver circuits between the power lock motor and the CTM as required. If not OK, replace the faulty power lock motor.