Heating and Ventilation

Heating and Ventilation

The heating and defrosting 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
- System uses a reheat method to provide conditioned air to the passenger compartment
- The blower motor draws outside air through the air inlet duct from just below the windshield during all system operations except for MAX A/C cooling (when recirculated air is used)
- All airflow from the blower motor passes through the A/C evaporator core
- Regulates the temperature by reheating a portion of the air and blending it with the remaining cool air to the desired temperature
- The temperature blending is varied by the air temperature blend door, which regulates the amount of air that flows through and around the heater core, where it is then mixed and distributed
- Engine coolant flow through the heater core is prohibited by the heater control valve when the system is set to MAX A/C (manual climate control), or as determined by the HVAC module in the AUTOMATIC mode


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.


Heater Control Valve

The heater control valve is actuated by the air inlet door vacuum control motor circuit (manual climate control) or the heater control valve vacuum control circuit if equipped with Electronic Automatic Temperature Control (EATC). When the heater control valve is closed (full vacuum), coolant flow through the heater core is cut off and A/C cooling efficiency is increased.