How a central locking pump works in a car

Genuineguy

Hi ,

I was wondering could someone explain to me how a central locking pump works, i.e. how it is able to activate the door locks in a car. I always taught these were activated with solenoids, rather than air. Does the doors locks have both an electrical activater and some sort of a air mechanical switch to lock the doors, Can someone explain to me how this is done.

Many thanks

stylers

they don't all use pumps, but usually found in VAGs (vw, audi etc) and mercs. basically there is a small motor driven air pump in the boot which is reversible or can both pump or pull a vacuum. this is connected to a small bellows/piston in the lock mechanism by a pipe out to each door. it usually pumps air to unlock, and pulls vacuum to lock. There is a pressure switch in the pump unit which tells the controller when the doors are locked/unlocked as the pressure/vacuum increases when the locks are up or down fully. If there is a leak in the system, the pump will operate for longer than normal, and time out eventually..

fully electrical locks usually use a small motor to drive a rack and pinion in the lock mechanism. modern locks are a self contained unit, older systems (where central locking was optional) usually had the actuator seperate from the lock..

Genuineguy

Thanks Stylers for explaining how this works, I have an Audi myself, And was curious of how the central locking operated,

Thanks Mate

stylers

your pump is in the boot.. main thing to watch out for with this system is excessively long pumping time caused by leaks..