The Air Conditioner / Heater Temperature Blend Door Kit is the last piece needed when the Temperature control knob is hard to turn on the Lancer and Outlander. WARNING: Advanced mechanical skills are needed when replacing. The heater box must be removed and taken apart from the car to replace. This requires taking the Freon and the coolant (antifreeze) from the car. A good mechanic may take 6 hours to replace it. SEE RETURN POLICY!