an electronic control unit is used, a complete diagnosis of its failures can be made only with the use of special equipment in a car service workshop. The single lock control unit is located under the instrument panel, to the right of the fuse mounting block.
The functioning of a single lock occurs due to the operation of bidirectional electromagnets located in the car doors. The control switch has two positions: LOCKED and OPEN. When activated, the switch sends a ground signal to the door lock control unit, resulting in the appropriate switching of the actuators. Depending on the initial position of the switch, when it is switched, the control unit simply reverses the polarity of the current supplied to the electromagnets.
Some models may be equipped with an anti-theft system included in the vehicle's single lock. If you cannot find the cause of the system failure during the checks listed below, drive the car to a workshop for a more complete diagnosis.
1. Always check the condition of the loop protection first. Be aware that on some models the single lock circuit is protected by a combination of breakers and fuses.
2. Toggle the control switches in both directions with the engine off. Listen for clicks that accompany the operation of the electromagnets.
3. Check the continuity of the switches in both positions (see accompanying illustration and table below). Defective switches must be replaced.
4. Check the conductivity of the wiring in the section of the circuit between the switches, the control unit and the electromagnets of the activators. Repair damaged wiring.
5. Check the grounding of the switches and the control unit.
6. If only one of the activators fails, remove the interior upholstery panel from the corresponding door (see chapter Body) and check the correctness of the voltage supply to the executive electromagnet by switching the control switch. One of the wires must be powered in one of the positions of the switch, the second - in another (see accompanying illustration).
7. If the voltage supply is correct, replace the solenoid.
8. If voltage is not applied to the activator, check the appropriate section of the circuit (between activator and control unit) for breaks and short circuits.
Note. Most often, damage to the wiring occurs in the sections of the harness between the door and the car body and is the result of dynamic loads applied to the harness when opening and closing the door.
Single lock control switch status map
Switch position | Conductivity between terminals |
LOCKED | 1 and 2 |
OPEN | 2 and 3 |