Ok i have a 1979 300D and the problem is when every time i turn on the a/c or Heater (on any setting) it only blow air to the far left, right and the window defroster vent, but the two middle vents slghtly blows air. There is nothing wrong with the vaccume system it works fine.

Any solution's?

Thank's

 

Do a "search" for center vent. many questions and good answers there. Go to the top of the page, click on search in the blue header, type in center vent.