Air Handling
Based on the climate control system settings the heater core and evaporator core housing directs airflow through the evaporator core and the heater core as needed, with the airflow exhausting through the appropriate outlets. Door actuators control the internal doors of the heater core and evaporator core housing to direct the airflow as selected by the climate control system settings. The air source is from outside air or recirculated passenger compartment air as determined by the air inlet mode door position.
The defrost/panel/floor mode door, temperature blend door and air inlet mode door actuators use a potentiometer to sense and communicate the door position to the HVAC module. When an airflow mode, desired driver or passenger temperature, or fresh air or recirculation mode is requested by the HVAC module the appropriate door actuator motor(s) is driven to the desired position, using the position sensed by the door actuator potentiometer to accurately position the door actuator.
The HVAC module will adjust the air inlet door depending on the humidity measured by the in-vehicle temperature and humidity sensor. If the vehicle cabin becomes too humid and recirculated air is not selected, the HVAC module will adjust the air inlet door to allow more recirculated air. When the humidity level drops, it will adjust back to fresh air. The HVAC module will also make system adjustments based on in-vehicle temperature.
The HVAC module uses the blower motor speed control to control the blower speed. REFER to CLIMATE CONTROL - EMTC , BLOWER MOTOR SPEED CONTROL .