2. Check the door lock linkage. The door lock linkage is a series of rods and levers that connect the door lock actuator to the door lock. If any of the linkage is damaged or disconnected, it will not be able to lock the door properly. To check the linkage, you can open the door and look inside at the door lock mechanism. If any of the linkage is damaged or disconnected, it will need to be repaired or replaced.
3. Check the door lock solenoid. The door lock solenoid is a magnetic device that helps to lock and unlock the door. If the solenoid is faulty, it will not be able to lock the door properly. To test the solenoid, you can try to lock and unlock the door with the key. If the key works, then the solenoid is likely faulty and will need to be replaced.
4. Check the door lock motor. The door lock motor is a small electric motor that drives the door lock actuator. If the motor is faulty, it will not be able to lock the door properly. To test the motor, you can try to lock and unlock the door with the key. If the key works, then the motor is likely faulty and will need to be replaced.