Defrost Issues

Discussion in 'The Big Chill' started by Stampy, Nov 27, 2007.

  1. Stampy

    Stampy Well-Known Member

    My car is 1966 Skylark with factory AC. Its got the two slider switches, one controlling Hot or Cold, and the other controlling Defrost, Heat, or AC.

    Hot + Defrost= Radiant heat from the defrost vents, no air pressure.
    Hot + Heat= Nothing.
    Hot + AC= Hot air from AC vents.

    The AC works fine in any position. What gives? Something not routing right inside the dash?

    ~Mike
    '66 Skylark 340-4
     
  2. 70aqua_custom

    70aqua_custom Well-Known Member

    Mike, my book says your car's heat and a/c is controlled by vacuum. The first thing I'd do is start under the hood and start looking for leaks. A hose could be off or cracked. There will be a hose from the manifold to a canister/tank. I'd start at the manifold and work my way into the car. There's also a vacuum controlled water valve in the heater hose under the hood. Leaks can be in any of the hoses, the actuators under the dash or at the vacuum switch itself.
     

Share This Page