You can perform simple checks of the drive and connections yourself. More detailed checks and troubleshooting of serious faults are performed at a car service center. The locks are controlled by reversible electromagnets mounted in the door niches.
The lock switches have 2 positions: Lock and Unlock. The switch sends a signal to the control unit to unlock or lock the door. The control unit changes the polarity of the signal in accordance with the switch position, as a result the solenoid coil terminals are connected either to ground or to the +12 V power supply.
Some vehicles have anti-theft devices built into the door locks.
Diagram for checking the door lock electric drive switch on FJ60, 62 cars and the designation of the connector contacts
FJ80 Electric Door Lock Switch Test Diagram and Connector Pin Designation
Examination
1. First, the fuses and circuit breakers are checked.
2. When the lock drive is activated, a click should be heard in any position of the switch.
3. Check the door lock switch contacts for closure according to the attached diagram. If the contacts do not close according to the attached diagram, replace the switch.
4. If the switch is working properly, check for a break in the wires connecting the control unit, solenoids and switches.
5. Check the ground connection of the control unit and switches.
6. If only one electromagnet does not work, then check for voltage on it by removing the door trim. In the Lock position, there should be voltage on one of the wires. After moving the switch to the Unlock position, there should be voltage on the opposite wire.
7. If there is voltage, replace the electromagnet.
8. Otherwise, check the relay or the wire between the control unit and the solenoid. Typically, this wire breaks when the door is closed and opened.