It turns out the system had just lost pressure and running the engine for about 20 seconds solved the problem. Unfortunately, I didn't figure this out before I took the door apart. Oh well, I know a lot more about the central locking system now than I did 24 hours ago. and that panel isn't that bad to get on/off.

Thanks for the advice, everyone.

__________________
Ralph

1985 300D Turbo, CA model
248,650 miles and counting...