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.
Car Problem Reports
Mercedes-Benz CL600 Evaporator Temperature Sensor Failure
Mercedes-Benz CL600 Problem
Average Mileage: 97,666 mi (70,000 mi - 115,000 mi)