Air/Heat will blow out of the top vents(defrost) and middle vents, but air will not blow out of the floor vents. The cables are connected from the control knob to the side of something located on the wall between the engine and inside of the car and they move when the knob is turned.
Air will not blow out of the floor vents. on 2005 Toyota Corolla
maybe the mode door is stuck from the floor vents