Volvo Repair: Heating & A/C vents, vacuum hoses, vacuum switches

Question
I own a 1984 240GL driven daily with 327944 miles.  The shutters in the vent system for the heat & A/C do not operate.  I checked the vacuum hoses and they seem to be O.K.  The floor shutters are in open possition.

In addition the left side vents blow at a lower velosity than the right side which seem to blow at normal velosity.

Do these 2 problems have anything to do with each other?  Do you have any suggestions on how I correct the problem?  My main concere is no defrost on drver's side of windsheild.

I appreciate any help you can offer.

George

Answer
Hi George,
         The vacuum controlled venting system in 240's
  is a simple system to understand.Sometimes the vacuum operated servos/diaphrams will fail.
        these vacuum controlled units are easy to replace.
         Be sure that all of the vent flaps freely move..
         Be sure that the connections at the switch
        are in good order.
         These vacuum switches do fail...leaks.
         You'll figure it out.
         
         Keep me posted,

                             Bilbo