Strange, I just had air conditioning trouble on my 400E of the same year with almost the same amount of miles, a couple hundred off. I just moved from San Diego, my first name is Matt and my last name starts with D! Anyway on mine the belt tensioner went bad causing the belt to slip and turning the compressor off. It would be errie if that was your problem as well.
1992 Mercedes-Benz 400E
2002 Mercedes-Benz ML500