Hi again!

My '71 cutlass convertible has a black cylindrical vacuum cannister mounted to the firewall.
One port is connected to manifold vacuum, the other port seems to have been capped off.

Can one of you knowledgable guys tell me where this capped off port should be connected to? and perhaps its location so I can know where to find it?

Many thanks in advance!

 

That is the vacuum source for the HVAC controls. I'm not sure where it connects under the dash, though, as I never had to trace it. All I have seen on my car is the vacuum line coming out of the firewall and connecting to the vacuum canister.

 

Ah, thank you for the reply Fun71.

Anyone know where to look for the connection point?

 

The vacuum canister is simply an additional vacuum tank that provides vacuum to operate the HVAC flapper doors during periods of low manifold vacuum (like wide open throttle). The port closest to the engine connects to the manifold vacuum source. The port closest to the firewall goes through the firewall and connects to the A/C control head. Your chassis service manual has the hose diagram and connections.

 

Thank you Joe!
Where do I find this "A/C control head"? Is this the actual control panel assembly in the dash of the car by chance?

 

Yes it is.

- Eric

 

Thank you Eric!

Now if my Chassis service manual will just arrive already!

 

If you need an immediate fix, you can always join the nonprofit Historical Society at WildAboutCars.com for about $25 and download as much as your bandwidth will allow.

- Eric