Hi, Danny Boy,
Tyr squirting some WD40 into the mechanism through the edge of the door to see if that frees things off. Be careful you don't get it over the interior door lining. If that doesn't work, then it's door panel off, I'm afraid. The lock's operated by a solenoid thingy inside the door. When you press the button. a current goes through a coil in the solenoid and pushes a rod through the middle of the coil which unlocks or locks the door. When you get the door panel...be careful of the fasteners that hold it in place...try first of all oiling the various linkages that work the door lock...you'll see all of them running across inside the door. If that doesn't work...I'll be surprised if it doesn't as this is usually the cause of the problem, then it's the solenoid that's dodgy. It's quite easy to replace...a pull apart electrical connection and then disconnect the rod that goes to the lock. You should be able to get one from the main dealer, if not then your local scrap merchant should be able to help out. The most difficult bit of the whole thing is taking the door panel, but take it slowly and carefully and you'll be fine. While you're inside the door, squirt some WD40 over the whole lock mechanism and check the drain holes in the bottom of the door.
Go for it...it's not that hard a job!! Best of luck!!!
Denis (CarAid Mobile Mechanic)
Denis Langley
November 2007