Can anyone help me out. when I operate the central locking the passenger door button bouces up and down a few times. Sometimes it falls on lock but mostly it ends up in the unlocked position. It makes no difference how I opperate it, with the fob or the dashboard button it still has the same problem. I've just bought the Haynes manual but that just tells you how to take the door apart and doesn't offer any solutions. Any pointers would be greatly appreciated.