First have the freon level checked. If it is OK, then take a look at the Evap temp regulator.

To get out the pushbuttons, you just take out the ashtray and then the radio. There should be two screws under there and the wood will come out.

Good luck.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS