Commander 4WD V8-4.7L VIN N (2006)
Housing Assembly HVAC: Description and Operation
Rear
HOUSING-HVAC
DESCRIPTION
Models equipped with the rear heating-A/C system are equipped with a common rear heater and A/C housing (1) that combines A/C and heating
capabilities into a single unit mounted within the rear passenger compartment. The rear heating-A/C system is a blend-air type system. A blend-air door
controls the amount of conditioned air that is allowed to flow through, or around, the heater core (6). The rear A/C system is designed for the use of a
non-CFC, R-134a refrigerant and uses an A/C expansion valve (9) and A/C evaporator (8) to cool and dehumidify the incoming air prior to blending it
with the heated air. A temperature control determines the discharge air temperature by operating the blend door actuator (7), which moves the blend-air
door. This allows an almost immediate control of the output air temperature of the rear system. The mode control operates the mode door actuator (4)
that positions the mode-air door to direct the flow of the conditioned air out the upper or lower air outlets, depending on the position selected. Both
electric door actuators are connected to the vehicle electrical system by the HVAC wire harness (5). The rear blower motor (3) controls the velocity of
air flowing through the rear HVAC housing by spinning the blower wheel within the rear housing at the selected speed by use of the rear blower motor
resistor (2).
The rear HVAC housing must be removed from the vehicle for service of the mode door actuator, blend door actuator, blower motor and blower motor
resistor and, it must be disassembled for service of the A/C evaporator, heater core, mode-air door and blend-air door.
