central locking locks but wont unlock

rover 25

central locking locks but wont unlock it will unlock with the key.
also the passenger door will not open at all from inside or from outside and has no key hole on that side.
thanks for your help

 

If one of the doors wont open it could be a signal problem with the electrical microswitches. Your only option may be to remove the faulty door panel and see if you can lubricate the mechanism. Should be doable on a closed door on this basic model.