Borken door lock

[Michael_B._Patterson@hud.gov]

          Hey all,

          Need some help with my Father's 89 200.. From what i was
          told it seems that the door lock on the drivers side is
          broken.  The key will go in the lock and turn both ways but
          the doors wont lock or unlock from that side, It does
          however activate and deactivate the factory alarm?

          So is the lock busted or what?.. And easy fix??

          help is much appreciated!!

          Mike