After reading the Blue Bowtie's reply over, I went ahead and search the net again and again and found a vacuum diagram which makes him semi-correct.
Rather than connected directly to the Rotary Ported Selector/ Heater/AC Controls, the hard plastic vacuum line ( vacuum source ) through firewall connects to Black/gray In- Line Vacuum Hose Connector which connects to the Vacuum Harness which connects to the Heater/AC Control Assembly.
I went ahead and attached the diagram for anyone having the same issue.
Thank you Bowtie for making me look further.