Vacuum Lines for heater controls

I am trying to locate the part where a vacuum lhose labeled W2 goes to. I think it's a control pod for the heater's air intake, to recycle cabin air, or get fresh air for heat.

I looked in the FSM, and the mucrofiche files, and still can't locate the vacuum pod W2. Even the guy at the radiator shop says there isn't one! So he left it hanging, and when you put on the heat, you can hear the air sucking.

?

thx