No heat to my feet

My '99 has no heat coming from under the dash to my feet, heat still comes from the dash, and to the windshield, but nothing to the feet. If I put the dial to the feet setting it comes out the windshield. Before I start tearing anything out I was hoping someone would have been thru this before, or atleast point me to what I should be looking for. Any info would help, I appreciate it.

for saftey the system always defaults to defroster. likely a loss of vaccum. check the line at the right side of eng to the fire wall.

Iv'e got a similar problem with my '96 2.2 Extended cab LS. Except, on mine, the air only comes from the defroster and the floor. Doesn't matter what position the switch is in, it's stuck in defrost/floor.
I took apart the dash hoping to find a loose or disconnected vacuum line, but everything looked fine. Could the switch itself be bad? I didn't see anything obvious under the hood. Any ideas?

I'm sorry I guess im not sure where you're pointing me under the hood. I didn't see anything loose or hanging, nothing cracked that I could see to. Should I be looking on the driver side? or I assume the passenger side where the heater and its components are?

Drivers side follow the vac line from the engine by the PCV source and it runs to the canister and other things then the last connection is a plastic hose to the heater vac.

There is a hard nylon vacuum line attached to the intake (usually at the left side or rear on the V-6, right side of the plenum on the Mighty 134). The line is usually black. The line should connect through a check valve, then a "T" fitting to the vacuum reservoir attached to the underside of the hood or in the inner fender (depending upon year/model). The line after the "T" is routed toward the right (passenger side) and into a wiring harness, then routed through the firewall. It's common to have failures of the check valve, failures of the reservoir (ball), or inadvertent disconnection of the lines.

http://72.19.213.157/files/134EngineVacuumCan.jpg

Possibly a problem with the heat /defrost vacuum motor or blend door. Under the dash, left side of transmission tunnel, to the right of the gas pedal. Make sure the vacuum switches when the mode switch is moved. Make sure vacuum lines are connected. Make sure the vacuum motor moves the blend door.

Thanks for the help, Blue. Your advice was right on the money... I took a closer look at the vacuum line from the reservoir around the back of the engine and found it dry-rotted all the way through. New vacuum line at AutoZone cost about 4 bucks. Works good, last long time!

Thanks Again