Help! My Heater vent switch on the control panel in not working on my 96 Tahoe

Hi, My Heater vent switch on the control panel is not working. The blower and temperature switches work fine but I am unable to get heated air off the floor. I checked for vacuum lines and there isn't any. It appears everything is electrical. I have tested all fuses (under dash and hood) and found them to be working. I have checked the cables for power going into the heater control module and that is also OK. I'm not sure what else to do. The heat does not hit the windshield so it gets all foggy when it's cold. Any help is appreciated.