Apologies for making my first post a problem, but I have a problem with the ACC system in my 1993 300E2.8 that I can't quite diagnose.

First of all, there's no warm/hot/cold air coming out of any of the vents at all unless I push the 'EC' button, then I get some warm air when travelling at speed. Secondly, when I push 'defrost', 'bi-level', or 'normal' there's a squeal which I originally attributed to a siezed blower motor, but when I pulled the blower motor fuse and tried the ACC again I got the same squeal.

After some investigation, the squealing seemed to come from the heater control solenoids (close to the battery), and I know they're a common problem with the 124's, but I thought that these controlled hot water flow to the heater core and I'm puzzled as to why I don't get cold air from the air conditioner. Plus, why do I get warm air out of the vents when in 'EC' mode and at speed?

Perhaps I'm completley off - could it be the AC compressor, or the auxiliary water pump, but if so, why does the squealing come from the solenoids? And why does my blower motor not seem to be pulling air in regardless?