I have a 1972 Chevelle with air. This is not my car. I can't remember if I had this originally on mine or not. Can someone tell me what the curly hose going through the firewall just to the right of the evaporator box is? It looks to me to be some kind of vacuum line. I'm not sure if its associated with the AC or not. Is it needed? What is its function? Thanks ahead of time. Bob :beers:

http://inlinethumb58.webshots.com/41401/2279023470100380351S500x500Q85.jpg (http://good-times.webshots.com/photo/2279023470100380351nhkdbl)

Yes, you do need this. It is connected to the control head for the heater and AC. Vacuum motors move the doors that control the defroster, heater and so on.

Yes, you do need this. It is connected to the control head for the heater and AC. Vacuum motors move the doors that control the defroster, heater and so on.
Where does it connect in the engine compartemnt? I can't seem to see where it would connect. Evaporator box?

The little gizmo on that hose is a vacuum check valve which allows air flow from the heater/AC control to the engine. The hose from the check valve goes to the vacuum fitting ahead of the distributor.

The little gizmo on that hose is a vacuum check valve which allows air flow from the heater/AC control to the engine. The hose from the check valve goes to the vacuum fitting ahead of the distributor.

Wagner, thanks for the reply. Sorry to sound ignorant but I still don't seem to get it. From what your saying this is a vacuum line, with a check valve, which runs from the AC/ Heat control head to the vacuum on the distributor? So this line is necessary to provide vacuum to the AC/ Heater control head to provide vacuum to the motors that control the opening and closing of the differnt doors?

Whew :confused: I had to read it several times but if all the above is correct, then I'll have to get my vacuum from somewhere else. I have electronic ignition whith EFI (No vacuum pod at distributor) If anything I said above is not correct please advise. Thanks Bob

Not "ON" the distributor, on the vacuum fitting on the intake ahead of the distributor.

Not "ON" the distributor, on the vacuum fitting on the intake ahead of the distributor.

Understood, thanks Dean! Where might one find a check valve vacuum line like this?