Heater Vacuum Supply Location?

[75Lemans]

Hey guys,
New guy here. I am restoring a 1975 Lemans with a 350. It was a hack job from the previous owner. Trying to restore back to its glory days.

Problem: Heater control on the dash blows air but will not change location (vent, floor, etc).
I traced the vacuum lines through the firewall and they both go into the round, black vacuum canister. There is no vacuum source. I assume the previous owner couldn't figure out where to hook them up so put them here.

So I guess the first thing I need to know, where does the heater control panel get vacuum from?

Thanks for the help!

PS. I tried searching the forum before posting but I could not find any other posts talking about this specifically. Hopefully I have given enough detail.

 

[melsg5]

The vacuum canister should have another port that connects to the intake manifold to provide vacuum. Recommend the 1975 factory shop manual.

 

[75Lemans]

Found it! The vacuum ports are in front of the carb on the intake manifold sticking straight up. They were capped off by the previous owner. Hooked them up and heater control is swapping over properly.

 

[melsg5]

Found it! The vacuum ports are in front of the carb on the intake manifold sticking straight up. They were capped off by the previous owner. Hooked them up and heater control is swapping over properly.

Ok, just make sure the port you selected supplies vacuum at idle and while cruising.