This is really going to wind you up, but desperate as you are, have you tried taking the panels off the other door to examine the lock mechanism on that one? I know the drivers door lock and passenger door lock are different, mainly because the passenger door has a key lock, but you may get some clue. Also, have you tried removing the battery terminals and going through the rigmarole to reinitialize everything? I know it is the original mechanism, but you never know, and it doesn't take long.
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