I have a 1996 C220. The AC was working fine, and then the EC light came on and stayed on, not allowing the AC to operate. This happened once before, and I took the car to a very reputable AC shop(recommended by MB shops). They said the system was fine and reset an AC code. They couldn't find any probs. Everything was fine for months until today when it happened again. Since I think this is an OBDII system, battery disconnection won't work, will it? Any other things to check in the AC system? Anybody ever heard of this prob before?