The evaporator temperature sensor can fail, causing the AC compressor not to cycle. If the AC compressor does not turn on, the AC system will not blow cold air. If the compressor is stuck on, the air will be very cold at first, before warming up.Google+
Car Problem Reports
Mercedes-Benz C280 Evaporator Temperature Sensor Failure
Mercedes-Benz C280 Problem
Average Mileage: 211,666 mi (140,000 mi - 248,000 mi)
Visitor, 1999 Mercedes-Benz C280, 140,000 mi
AC shoots out hot air WHEN THE OUTSIDE temperature goes above 90 degrees. It is NOT a hot engine but HOT OUTSIDE TEMP. Three shops 'cannot' find anything wrong with AC as they keep car overnight and in the cool morning everything works great. NOT I hope to finally get this corrected.
Visitor, 1994 Mercedes-Benz C280, 247,000 mi
compressor is working but will not get cold
Compressor won't kickin, Replaced with new compressor, serviced refrigerant but no help.