The central locking relay is a key part of the electronic central locking mechanism on a vehicle. This system is complex, and consists of various actuators and relays. Power is sent to the central locking relay from the battery, via a fuse. The relay then sends this power to the actuator, and the actuator opens the door lock switch. To close, the polarity is reversed. The central locking relay is usually located in the driverside door behind the door trim.
Because of its position, it’s possible the central locking relay may get wet as a result of localised rust. This will cause the central locking relay to malfunction, and will need to be replaced. Other damage to the central locking relay can be caused by faulty wiring. If there is an issue with the central locking relay, or any other part of the central locking system you will be unable to operate the central locking system. This means that you will be unable to lock or unlock doors causing potential security issues. It’s therefore important to repair any central locking issues as a matter of urgency.