Central locking problem?

[sillywotsit1993]

So here's my question my central locking is dodgy the key doesn't lock or unlock doors I have to use the barrels. Now this is the Patten to lock car. Lock passenger door which looks the rear pass door to. Then go to drivers rear open door lock drivers door and then lock rear driver door. This problem is doing my head in. It'll open all doors at once but not lock them ????