Strange problem with my SL500 A/C. It works fine and blows cold air from the vents for awhile (1/2 hr?) and then it acts like it "freezes" up and the airflow slows to almost nothing. If I push EC and turn the compressor off then it will gradually increase the airflow from the vents and eventually become warm. Then I can turn on the compressor agin and it will do the same type of cycle. I have 2 people look at this and have had the system charged, etc. but it still does the same thing. Is there a control or something that does this automatically instead of me having to do it manually? Thanks loads for any suggestions as this is frustrating on longer trips.

 

The compressor is turning your evaporator into a block of ice. The first thing I would check is the signal from the evaporator temperature sensor through built-in diagnostics. The procedure for a '96 and older car is here: http://www.mercedesshop.com/shopforu...d.php?t=86546; later cars here: http://www.benzworld.org/forums/r129...air-vents.html.