Toyota 69120-06010 Actuator Assy, Front Door Lock, LH

Firstly, a power door lock system consists of switches, Door Lock Actuator, a control unit, and wiring. To diagnose faults, check the wiring connections and actuators for issues. The system uses bi-directional solenoids, with lock switches having two positions: Lock and Unlock. When the switch is activated, it sends a ground signal to the control unit, which reverses polarity to the solenoids to lock or unlock the doors. Check circuit protection first, as vehicles may use circuit breakers and fuses. Operate the door lock switches in both directions with the engine off, listening for the solenoids' click. Test the switches for continuity and check the wiring for continuity too. Check for bad ground at the switches or control unit. If all but one lock solenoids operate, remove the trim panel from the affected door to check for voltage at the solenoid. If it receives voltage, replace it. If not, check the relay for an open or short in the wire between the solenoid and control unit. For a keyless entry system, it consists of a remote control transmitter that sends a coded infrared signal to a receiver and may also engage the alarm system and provide a panic button. Finally, replace the transmitter batteries when the LED light doesn't light up.

Faults in the power door lock system can usually be diagnosed by checking the wiring connections and actuators for minor issues that can be easily repaired.