Air Distribution and Filtering

NOTE: The air distribution system of this vehicle cannot be equipped with a cabin air filter.

There are 2 sources of air available to the air distribution system:

- Outside air
- Recirculated air

Air enters the passenger compartment from the:

- instrument panel registers.
- floor duct.
- windshield defroster.
- side window demisters.
- rear footwell duct (if equipped).

Passenger compartment air is exhausted from the vehicle through open windows or body air vents on the back panel of the cab.

Electronic Manual Temperature Control (EMTC)

Recirculated air is always used when the HVAC module is set to the MAX A/C mode and can be selected in any mode except DEFROST.

Air distribution within the vehicle is determined by the airflow mode selected. Airflow mode doors are used to direct airflow within the heater core and evaporator core housing. Electric mode door actuators are used to position these airflow mode doors.


Dual-Zone Electronic Automatic Temperature Control (EATC)

Vehicles equipped with dual-zone Electronic Automatic Temperature Control (EATC) use recirculated air only when the RECIRC mode is selected in any airflow mode other than DEFROST, or when required by the HVAC module in the AUTOMATIC mode during maximum cooling demands. The HVAC module will drive the air inlet mode door to the full RECIRC position, the full fresh air inlet position, or may stop at a mid-position based on the HVAC module cooling/heating requirements.

Air distribution within the vehicle is determined by the airflow mode selected, or by the EATC system in the AUTOMATIC mode. The air distribution mode on vehicles equipped with EATC can be overridden by the driver if desired. Airflow mode doors are used to direct airflow within the heater core and evaporator core housing. Electric mode door actuators are used to position these airflow mode doors.

Vehicles equipped with dual-zone EATC use 2 separate temperature blend doors. This allows individual temperature settings to be selected for the RH and LH air outlets. The airflow mode doors are not partitioned for separate RH and LH airflow positions. Therefore, the airflow mode will always remain similar for the RH and LH sides of the vehicle regardless of the temperatures selected.