Hello,
I have a Mercedes w201 190 2.5 diesel.As the hot days are coming,I checked the A/C system of the car.When I turn on the a/c it starts working fine but after a few minutes it cuts off,and never turns on again.I checked the Freon(mine is on R12)and it's reading fine.When the A/C was working it cools properly so I think the compressor is doing his work when it's working.I think it's something from electrics.
I take off the relay (near the battery) for a few seconds and when I put it back the A/C starts again(reset),not for too long.and I repeted this for few times but it stills shut off after a few minutes.
Does any one experience this problem,from where I have to start checking the electric components?
Thanks

A malfunctioning evaporator temp sensor will cause the exact condition that you described. The sensor is supposed to cut power to the compressor when the evaporator temp approaches the freezing level, to prevent the evaporator from icing up. When the sensor malfunctions, it can trip at much higher temps.

You might try pulling the sensor out of the evaporator (for test purposes only) to see if it solves the problem.

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1PY1E2LZD1SS0UKUJ0&year=1987&make=MB&model=190-DT-001&category=R&part=A%2FC+Evap+Temp+Sensor

Hi Thanks,
Can you please tell me where is this located exactly,and how I can check if it's this sensor?

It is in the evaporator under the dash. If you pull it out (leave it connected) so that it is not in contact with the cold air, the a/c should not cut off if the sensor is the problem. If it still cuts off, the problem lies elsewhere.