How is AC/heat control supposed to work

[kensousa]

Dumb question, but when is the vacuum supposed to open or close the air vent at the kick panel on the passenger side of my AC truck?
The driver side vent has the mechanical lever and even I can figure that one out...
I've been messing with the routing of the vacuum lines at the ac\heat controls, thanks to a schematic that I found here on the board.
Right now I have vacuum at the hot water valve, which seems right, but the vacuum opens the passenger side vent when I move the levers over to "air conditioning" mode.
I can't seem to get any combination of levers to close that vent unless I manually reach over and push it closed.
What is supposed to happen when manipulating the ac\heat levers in relation to that passenger vent?
Thanks