I have a 1978 300CD I am putting back on the road. The CCU seems to need to some help. The buttoms work, by work I mean the blower goes and air is directed at various speeds to the the various vents, but when heat is required none is produced. I tried it this morning when the ambient temperature was arount 40 degrees - no heat even after the engine was up to operating temp.

I see in other posts that the vacum system's integrity can be verified to some extent based on how the tranny shifts.... shifting in this car is smoooth.

So where should I look.


Thanks


Tim

Could be the monovalve not working anymore. Lots of posts on here about how it works and how to replace it.

Tim[/QUOTE]