Heating and Ventilation

Heating and Ventilation

The heating and defrosting system:
- controls the vehicle air temperature, and during air conditioning (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 blower motor speed.
- allows temperature to be adjusted individually by the driver and the passenger to maintain comfort.
- uses a reheat method to provide conditioned air to the passenger compartment. All airflow from the blower motor passes through the A/C evaporator core. Temperature is regulated by reheating a portion of the air and blending it with the remaining cool air to achieve the desired temperature.
- blends the air temperature by regulating the flow of air through or around the heater core.

The blower motor draws ambient air through the cabin air filter during all system operations except for when the auto system switches to recirculation for maximum A/C performance, or when the ambient air temperature sensor requires the system to be in recirculation mode or when recirculation is manually selected.

Heater Components:

Heater core
The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer it to the air passing through the heater core and evaporator core. The heater core and evaporator core is separated into two sections. Air passing through one section is directed to the driver side of the vehicle, while air passing through the other section is directed to the passenger side of the vehicle.

Auxiliary coolant flow pump vehicles fitted with 3.5L or 4.2L engine
The auxiliary coolant flow pump is electrically driven and provides increased coolant flow during low engine speed operation. The pump is also used to circulate coolant after the engine is turned off under certain conditions.

Blower motor
The blower motor pulls air from the air inlet and forces it into the heater core and evaporator core assembly where it is mixed and distributed. The blower motor has eleven speeds (vehicles with telematics have seven speeds) and is controlled by the climate control assembly.