W350 1 Ton Pickup 4WD V8-360 5.9L VIN 1 4-bbl (1988)
Power Door Lock Actuator: Testing and Inspection
To determine which door lock motor is defective, check for proper lock/unlock operation at each door. If neither of the door lock motors operate, the
problem may be due to a shorted door lock motor. Disconnecting the defective door lock motor will allow the other to operate. If the system operates
properly with a door disabled from the system, then that door lock motor may be defective.
To test an individual door lock motor, remove the door trim panel(s) to gain access to the door lock motor. Unplug the door lock motor connector and
connect a test light between the two wires of the wiring harness. Move the switch to the lock and unlock positions and check for power. If power is
present in both switch positions, the door lock motor is defective. If power is not present in one position or neither positions, the switch or connecting
wires may be defective.
