I had a hard time finding good information on how to remove the manual door lock. The procedure I did find was for a MB, and it worked, but was very time consuming. It involved removing the door panel and actually the door latch mechanism. There is an easier way, that may have been posted but I couldn't find it, and if it saves someone some time and aggravation, it's worth posting again (IMO). If your key will not unlock the door, and you don't want to wait till you have a dead battery to find this out, there is a pretty simple solution. what happens is you insert the key, it will turn but not engage anything. The problem is the T shaped link between the lock cylinder and the latch mechanism falls out. If you pull the weatherstripping on the edge of the door starting at the top, you will see a little hole. You can insert a LONG allen wrench in there, and after a bit of searching, fine the allen screw that holds the lock cylinder in. It is supposed to be a captive screw, but mine wasn't. Just unscrew it until you can feel the lock move. If if is loose enough, you can pull the door pull and the lock will come out. I would leave the allen wrench in place to kinda hold the screw in. On mine, the long T shaped piece and the roll pin had both fallen out. They were down in the bottom of the door and you should be able to retrieve them without taking the door panel off. there is a hole about the size of a silver dollar in the bottom of the door and you may be able to get them out through there. If you do have to remove the door panel, which is a PITA, there are very good write-ups on that here on how to do that. Anyway, when you find the T shaped piece aND IF YOU ARE REAL LUCKY,the roll pin, you just put the piece back in the lock and put the roll pin back through. I mushroomed the ends on mu roll pin so it shouldn't fall out again. It doesn.t matter how you put the T piece in as long as you can get the roll pin in. Putting the lock back in can be a little tricky. You HAVE to make sure it will engage the lock mechanism in the door latch, and it took me several tries, well to be honest, I got my son who is a locksmith to do it for me. Make sure the mechanical lock works and button everything up and you are good to go. Hope this helps!!