Hi, I replaced the compressor, expansion valve and filter in dryer but a.c. still only blows hot air. I evacuated the system and added Freon to specs on decal. All I can think of is maybe there are codes in the system preventing the compressor from activating? Any help is greatly appreciated.

 

Well from what my friend working at DSRLeasing told me it could be that coolant is entering the heater core all the time. Mercedes had 2 ways of doing this from that era. The earlier version had a vacuum water valve against the rear firewall. The other version had an electric valve called a mono valve by the battery tray. I would think it would be very likley to knock of a vacuum line doing an oil change but most likley you would have other problems as well.

 

I will look into both of those possible causes. Thank You!