The HVAC heater blend door actuator is an electric motor that manages the flow of air by sending it out through various vents. It can also send air away from the heater core if you don't want warm air going through the vents.
Blend door actuator functionIn a vehicle's HVAC system, the blend door actuators help manage the air temperature from the vents. It also directs air to the selected vents, and to blow out hot air to the interior, the blower motor needs to transmit air to the heater core. Also, when you don't want heat, the blend door actuators send airflow away from the heater core.
Common issues with a faulty blend door actuatorA faulty blend door actuator can lead to a lack of heat, A/C, and uncommon noises.