I had my '84 300D in the shop last week for a cooling system flush/change. Now that the car is back, I note that the ACC blows only heat. I have read here that this may be a bad monovalve. Is it possible that the cooling system work could lead to a bad monovalve?

Silly question from a newbie: Is the "monovalve" the same thing as the "heater control valve" shown in the Haynes manual on pg 112?

Thanks all. Great forum here.

Mark