When totally inoperative try wiggling the key. The electrical portion of the ignition switch is a common problem that knocks out everything. The ignition switch has more than one output circuit and the one powering the AC fails quite often while the ones powering engine systems hardly ever fails. Guess it is nice they fail that way.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician