Did you take the under-dash panel off?

But if you are able to regulate temperature and air flow, then the servo is working.

Does the compressor come on with DEF? If so, you probably have a vacuum problem that is preventing it from getting power in the other positions. If not, you have some sort of AC problem like low freon.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe