AC system leaks and/or a faulty evaporator temperature sensor can cause poor AC cooling. The failed sensor can prevent the AC compressor from coming on. Leaks cause a low refrigerant level, which reduces the ability to cool.Google+
Car Problem Reports
Mercedes-Benz ML350 AC System Leaks/Bad Temperature Sensors May Cause Poor Cooling
Mercedes-Benz ML350 Problem
Average Mileage: 92,141 mi (80,000 mi - 100,000 mi)
Visitor, 2005 Mercedes-Benz ML350, 100,000 mi
Air condition stop working ,just fan on ????
At times when i on the A/C system it will work fine and if i move for about 4km it will stop working and at times it will not stop working by not cooling, only blowing air.