I just bought a 2001 C320 yesterday. Problem I am having is with the A/C system. When I turn the A/C on, I see that A/C compressor kicks in but I get no cold air in the cabin also, there is this button which says" A/C OFF" on it. It lights up. How can I diagnose this problem, or what could be wrong with it? There is freon in the system and no leaks at all. Any ideas and help will be appreciated.

Here's how I get max cooling in my '01 C320 and this will be a good way to see if your system works. BTW, it has R134A in it, not Freon.

Lower the temperature to LO on each side by repeatedly pushing the "lower temp" buttons.. Press the two round buttons in which will turn the AC on in Auto mode. Rotate each button slightly to turn off the red lights in them and be sure that the arrow then points to the left which opens the dash vents only. Be sure the AC off button is dark. Modulate the fan speed manually with the fan speed buttons. This method will give the lowest outlet temps and will cool the car even in 100 deg plus weather.

As to the compressor, it is a swashplate compressor, infinitely variable and has no clutch and there is no way you can feel it starting or stopping since it varies the coolant flow depending on demand and changes the pumping rate slowly. That's why when you turn the compressor off manually that it takes a while for the cool air to warm up.

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Roger E.