ACDelco GM Original Equipment HVAC Heater Blend Door Actuators are electric motors that receive a signal or command from the HVAC controller and either open or close the heater blend door, which determines the temperature of the airflow through the HVAC vents. These original equipment HVAC heater blend door actuators are GM-recommended replacements for your vehicle's original components and have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.