Heater not blowing on floor

Your Mode Door and /or actuator is likely broken. The mode door actuator is connected to the body control module (BCM) through the vehicle electrical system by a dedicated five-wire lead and connector of the HVAC wire harness. The mode door actuator can move the panel-air door and the floor/defrost-air door (mode-air doors) in two directions. A potentiometer within the actuator allows the BCM to know the exact position of the mode-air doors at all times.