The overheating and AC seem to be linked - my car loses refrigerant slowly. Have to charge it every year at about this time, but I have yet to experience the situation you described. Does the car overheat if you push the "economy" button? That should shut the compressor off.

The window is guided in tracks with plastic runners that can fail if the grease takes on a lot of dirt and dust over time. The end symptom is the mechanism fails. I have replaced the rear window operating mechanism, but not the fronts. Kind of a cheesy set up on the rears.

I have found the light bulb that illuminates the rear license plate is the one that fails and is most difficult to detect. Huge pain to replace as well - you get to it from behind the bulb under the trunk lid liner. Anyway, it is on the circuit to trip the dash warning, and it is not that apparent (there are two of them) when you walk around the car to inspect bulbs.

Good luck,

Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)