Paul Noll's 2009 Toyota Prius

Right Steering Wheel Controls - 28

The top left button will switch the air being circulated from outside the vehicle to inside and the reverse. It is especially good when you pass through some smoke or smelly area or are following a vehicle spewing excessive smoke. The other two buttons control the defrosting on the front and rear windows. The square symbol controls the rear window and energizes the embedded wires in the rear window to defrost it. The symbol with the round top directs the heater air flow to be directed to the vents below the front window.