What is the name of the heating part that changes the airflow from the foot area to the vent area?

The component responsible for changing the airflow from the foot area to the vent area in a vehicle's heating and air conditioning system is known as the blend door. The blend door operates within the HVAC system and regulates the temperature of the air entering the cabin by mixing hot air from the heater core with cool air from the air conditioning system. By adjusting the position of the blend door, it can direct airflow to different parts of the cabin, such as the vents for upper body heating or cooling or to the footwell for heating.

This function is crucial for ensuring comfortable cabin temperatures and proper airflow distribution. Understanding the mechanism of the blend door is essential for diagnosing HVAC issues, as malfunctioning doors can lead to improper temperature control or airflow.

Other options like the bypass door, compression door, and blower door serve different functions within the HVAC system or are not standard terminology typically associated with the component that specifically adjusts airflow direction between the foot and vent areas.