The a/c system on my c class 2001 does not turn off when i press the button, it just blows freezeing cold air all the time

OUTSIDE AIR: Press this button to direct the system to use outside air.
Pressing the OUTSIDE AIR button will cancel the RECIRCULATION button.

RECIRCULATION: Press this button to limit the amount of outside air entering your vehicle.
This is helpful when you are trying to limit odors entering your vehicle or attempting to quickly cool down the interior. Pressing RECIRCULATION will recirculate air continuously.

RECIRCULATION is used when the fan control is OFF to limit odors, outside air and dust from entering your vehicle. All button lights will go off. The last setting selected will activate when the blower is turned back on.
Pressing the RECIRCULATION button will cancel the OUTSIDE AIR button. To return to normal operation and to prevent stale air, be sure to return the OUTSIDE AIR.

Between HEATER and BLEND mode, outside air is forced to reduce window fogging. If the RECIRCULATION button is pressed, the LED indicator will flash three times indicating that forced outside air is activated and RECIRCULATION is not available.

I think what your experiencing is normal. If you want to keep cold air form coming into the cabin, press the recirc button.

I hope this helped,

sounds like water pump is broken

Are you saying the fan will not come on or it comes on but it only blows cold air?

EC stands for air conditioning. Have you charged the air conditionning with gas. is the air conditioning pump making a clicking noise when you press the EC button.

Sounds like your thermostat is on it's way out. Do a good cooling system flush then replace thermostat.

it think you are freezing out, try cleaning the condenser coils

AC will not work with temps are cold even when it is turned on. The air is colder cause the temp is colder. The AC cycles in hot weather because the AC charge is low and needs recharging. You will know this if you open the hood run the AC and you will hear the clicking sound of the AC compressor magnetic clutch. You can recharge it easily buy buying a compatible can of refrigerant. I suggest buying the kit with the gage so you don't overcharge the system which will cause freeze ups

maybe the heater matrix could be at fault, thats the bit that controls the temperature in the car.

Hi,it sounds like your a c swjth or the blower motor burned out,that is the reason for the smoke ,

Look under the hood and if the A/C is blowing cold and there is ice forming on any of the lines (especially the high side) there is a clog in the system somewhere.  The cheapest place to start is putting in a new expansion valve a/k/a orifice tube.  Freezing up is usually a result of a clog somewhere in the system.