Heater control that directs flow of air to windshield, floor, or dash panel does not work. Replaced switch, still does not work. There must be a motor somewhere that directs the airflow. Blower motor works.
I believe your vehicle's HVAC system is actuated by engine vacuum. Have you checked for leaks under the dash? Also, check the supply line from the engine. It goes through the firewall and into the vehicle.