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 brushless 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 engine coolant to separate halves of the heater core. A dual coolant flow valve is used to control the flow of coolant.

The blower motor draws ambient air through the cabin air filter during all system operations except for MAX A/C cooling (when recirculated air is used) and OFF.







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. The heater 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. The heater core has separate inlet ports with a common outlet port.

Dual coolant control valve
The dual coolant valve regulates the flow of engine coolant to each half of the heater core. Two electric solenoids, Which are individually actuated by the heater control module, are the control elements. The valve contains three ports:
- inlet port - coolant from the engine
- outlet port - coolant to driver side of heater core
- outlet port - coolant to passenger side of heater core

Auxiliary coolant flow pump vehicles fitted with 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 brushless blower motor pulls air from the air inlet and forces it into the plenum 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.