mode actuator switch for vents is not working. only blows on floor

I think I have a vacuum problem. I have found what I think is where the vacuum line connects to the firewall. It is a 90 degree rubber boot that connects to about a 1/2 tube that goes through the firewall. My problem is that it looks like the vacuum line was ripped off of the end of the boot. I don't see the other end of the vac. hose and I am wondering if this is the correct place that it goes through the firewall and where on in intake that the other end of the vac line might be connected. I can't locate it. Anybody there that can help? thanks.