Have a 96 Discovery , central locking works to lock . But on 3 doors you cant open them from outside and you have to hold up the lock manually to open the door . What could it be .. need help as i need it to be road legal .

 

You have to adjust the linkage inside each door. It gets desajusted with time. They have thread so you can tight the links. They are very sensitive, adjust one turn at the time, and test, turn, test. I am sure someone has posted pictures here somewhere.