Vacuum hose connections along the firewall?

Hello,

My question relates to the vacuum hose connections along the firewall. Where do they connect and their purpose. 2000 Ford Taurus SE VIN Code U. I recently replaced my spark plugs and wires. After removing the passenger side cowl I noticed a loose vacuum hose. I thought I could find the other end of the hose because it is approximately 6 inches long, and the connector on the vacuum feed line (clipped to the cowl) points towards the firewall. In the interim, I have plugged the connection that runs under the cow. The problem I hope this will fix pertains to the AC/Heat air direction switch, as it will only blow air out the windshield vents.

Thanks

Paul