Heating and Defrosting

HEATING AND VENTILATION

The heating and ventilation system has the following features:
- Controls the temperature and, during A/C operation, reduces the relative humidity of the air inside the vehicle.
- Delivers heated or cooled air to maintain the vehicle interior temperature and comfort level.
- Controls the A/C blower motor speed.
- Cooling or heating can be adjusted to maintain the desired temperature.
- Uses a reheat method to provide conditioned air to the passenger compartment.
- The blower motor draws outside air through the air inlet duct, except for MAX A/C (manual climate control), or when the RECIRC mode (EATC/DATC) has been selected.
- All airflow from the blower motor passes through the A/C evaporator core.
- Temperature blending is controlled by the temperature blend door(s), which regulate(s) the amount of air that flows through and around the heater core, where it is then mixed and distributed.

Heater Core
The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer it to air passing through the heater core.

Blower Motor
The blower motor pulls air from the air inlet and forces it into the plenum assembly where it is mixed and distributed.

Plenum Chamber
The plenum chamber directs airflow from the blower motor through the evaporator core and heater core. All airflow from the blower motor passes through the evaporator core. Airflow is then directed through or around the heater core by the temperature blend door(s). Vehicles equipped with DATC use a partitioned plenum chamber with two electric actuator-positioned temperature blend doors. This allows for separate temperatures to be selected for the driver and passenger sides of the passenger compartment. Manual systems and EATC systems use a single electric actuator-positioned temperature blend door to direct airflow through or around the heater core.