$25 plus shipping This is the part that’s hidden behind the passenger side kick panel. It enables the air conditioning and heater system to function at it's best by working in conjunction with a similar unit in the cowl to block off fresh air from entering the car, forcing cooled air back through the evaporator unit and back in the car at at a lower temperatures. If your air conditioning doesn't seem to be functioning correctly, there's a good chance either the valve, the door, the spring or a combination of these pieces need to be replaced.