What year/model is the car? My understanding is that system goes into EC mode to keep compressor off and not damage it.

Hope you don't mind if I tell my A/C tale of woe. My '97 E320 quit cooling while it was sitting idle for a week. Not knowing what the problem was, I engaged the EC button to keep the compressor from running. Dealer says that it needs a new evaporator and that it will take 20 hours and cost $3500. I know that the S class cars of the 90's have big labor bills and bad evaporators but I have not heard of this problem with the W210 cars. Can anybody share their experiences?