I have a 2004 opel corsa, 1.0 ltr with 5 doors. There is a problem with the central locking system. When I press the button on my key it only works on the driver door and left rear passenger door. I have to manually lock and unlock the right rear passenger door and the front passenger door is now permanently locked no matter what I do with the key or lock button. I'm guessing I need new lock mechanisms for the doors but how do I open the front passenger door when the lock seems to be stuck in the locked position? I've even taken off some of the inside panel but cant seem to be able to get at the lock mechanism.