This is the mechanism through which car central locking work. On the interior of a car door there is the door-lock actuator which is the mechanism that controls the door lock. When the actuator is in operation, it normally moves the door locking latch either up or down. When the latch is in the unlocked position, the door handle outside of the car is connected to the opening mechanism. This makes the door to open and close at will. When the door locking latch is in the locked position, you will find that the door handle on the outside is disconnected from the opening mechanism.