The central locking solenoid/actuator 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 central locking solenoid, and the solenoid opens the door lock switch. To close, the polarity is reversed. The central locking solenoid is usually located in the driverside door behind the door card.
It’s possible that the central locking solenoid can fail. If this occurs the first thing to check would be the wiring. If this appears intact it’s likely to be an issue caused by another part of the central locking system. Any issue with the central locking solenoid or any other part of the central locking system will mean you are unable to operate the car doors causing potential security issues. In the case of a central locking solenoid failure it may be impossible to open the door from the inside of the vehicle. It’s therefore important to repair any central locking issues as a matter of urgency.