The central locking in a car operates using a manual system, a remote keyless system or a combination of both. A manual system involves the ability to lock all doors of a car, including the tailgate, by manually pressing a button. A remote keyless system operates in the same manner using a remote control that functions similarly to a television remote control.
The central locking system can access all doors, the tailgate and even the fuel lids. All central locking systems operate using an electro mechanical system that can be divided into the following subsystems: the remote control, which operates using either a coded infrared or radio frequency signal, the electric control module, which is the unit responsible for signal processing and the actuator.
The actual locking and unlocking of the central locking system is done by the actuator. There are two different types of actuators that can be installed in cars. They are:
- the solenoid system, which relies on an electromagnetic switch that locks and unlocks the door by passing a current through the electric control module in different directions
- the motor system, which relies on the rotary motion of the motor to control and convert the current motor direction using the rack and pinion mechanism