I own a 70 skylark custom and when i turn on the air the door that allows the air in won't open on it's own, I have to use something to prop it open. o No: Can anyone give me some help on where to start first.
The door is actually vacuum operated. Inside the passenger side kick panel you will find a vacuum diaphragm. Vacuum tubes should be black with an orange tracer & black with an green tracer. Green tracer applies vacuum to the diaphragm when calling for heat. Orange applies vacuum when fan is on. These go to the backside of the AC control panel & to a common connector harness. Verify you have vacuum in the tube before you go further. Could be a disconnected switch,loose & leaky connection. Check the linkage too, between the diaphragm & the door. Once you have established vacuum & still no go, likely you will need to replace the diaphragm.
