Heating and Ventilation

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.
- Cooling or heating can be adjusted to maintain the desired temperature.
- On vehicles with dual-zone electronic automatic temperature control (EATC), the temperature can be adjusted individually by the driver and passenger.

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 heater core and evaporator core housing and the plenum chamber where it is mixed and distributed.

Heater Control Valve
The heater control valve is actuated by the heater control valve vacuum switch (manual climate control) or the heater control valve vacuum control circuit (EATC). When the heater control valve is closed (full vacuum), coolant flow through the heater core is shut OFF and A/C cooling efficiency is increased.

Heater Core and Evaporator Core Housing
The heater core and evaporator core housing directs airflow from the blower motor through the evaporator core and heater core. All airflow from the blower motor passes through the evaporator core. The airflow is then directed through or around the heater core by the temperature blend door(s). Vehicles equipped with dual-zone EATC use a partitioned heater core and evaporator core housing with 2 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 use a single electric actuator-positioned temperature blend door to direct airflow through or around the heater core.