Heater Problems

I have a 1992 Cherokee Laredo. The air will only come out of the defrosters, no matter where its set. I can move it to vent, heat, bi-level, makes no difference. Any suggestions?

Those are run on a vacuum.

Have you worked on the Jeep recently? You could have knocked a vacuum line... or an actuator may have gone bad...

Tried to check vacuum lines, couldn't find any that were disconnected.

If you can't find a loose hose outside in the engine bay, pull the heater control out of the dash (easy to do) Just part way out so that you can get to the vaccum hoses. Check there and trace back if necessary. While youre there check control cable if there is one. Sometimes the end anchors become loose so when you move the control lever the cable does not open or close plenum door it connects to.