How can i get the central locking on my car working again? Many thanks :D?

Currently i have to use the key in the door. Please can anyone advise?|||might sound daft but have you replaced the battery in the key fob?|||a bit more info on your car would help. there are many different types of central locking system, which have different faults. for example, a VW golf uses a vacuum system, and the vacuum pump which locks and unlocks the doors often gets waterlogged and fails. On a mondeo a solenoid system is used, and these often become seized and fail.