I have an 1990 740 turbo with ECC air conditioning.
When the engine is operating in turbo mode i.e. foot down or accellerating
the face vents of the a/c stop blowing air.
I know this is a problem with the ECC on turbos so have checked the manifold
vacuum non return valves in the engine bay and the pipes to the valve unit on the ECC. They are ok.
I assume that this is a symptom of generally worn vac. motors etc. as the
system works ok in non turbo mode were there is plenty of vacuum.
There is a small vacuum reservoir in the ECC unit but what supplies vacuum
when the car is in continuous turbo mode,i.e. when moving at speed?
Will be gratefull for any suggestions.
Harry.