560sl Door Lock Not Working

Today I put the key into my 1986 560sl drivers door to lock the car, I felt a little resistance and thought it had locked. It hadn't. I went to the passenger side to try to lock the car I heard the usual noises of locks locking but the drivers door didn't lock. Does anyone have any idea what could be wrong? I know if I bring it to my usual mechanic he'll give me the run around and pay a minimum of $100. as his hourly rate is $85. per hour.
Thanks all,
Larry

[maheath]

Is it not activating the alarm either?

I had a strange alarm problem a couple of months ago and had to pull the fuse for the central locking system (#7 in my 560sl). Without the fuse, I had to lock each door individually and then the trunk last. Locking the driver's door always seemed to unlock the trunk.

Try pulling the fuse and see if you can lock it. Having the fuse out for a few minutes couldn't hurt. I had mine out for 2 weeks before replacing it with a brand new one and everything started working fine again.

The locks operate off of a vacuum system, so a vacuum leak may be a possible problem too. I haven't had to play with the vacuum system yet, so I can't help much there.

Thanks Mike,
I think I have found out what the problem is. I had a new door panel put on the car and now I find I can't move the locking mechanism from inside of the car either. I think they jammed the lock when they put on the new door panel.I'll bring it back to the shop that did it and I'll be prepared to hear "We didn't do that"Hopefully that's all it is .
Thanks
Larry