Durango 2WD V6-3.7L (2009)
Housing Assembly HVAC: Description and Operation
Rear
DESCRIPTION
Models equipped with the rear heating-A/C system are equipped with a common rear heater-A/C housing (1) that combines A/C and heating capabilities
into a single unit mounted within the passenger compartment. The rear heating-A/C system is a blend-air type system. A blend door actuator (7) operates
the blend-air door which 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 (5) and an A/C evaporator (4) 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,
which moves the blend-air door. This allows an almost immediate control of the output air temperature of the system. The mode door actuator (8)
operates the mode-air door which directs the flow of the conditioned air out the upper or lower air outlets, depending on the discharge air temperature
selected. Both electric actuators are connected to the vehicle electrical system by the rear heater-A/C wire harness. The rear blower motor (2) controls
the velocity of air flowing through the rear heater-A/C housing by spinning the blower wheel at the selected speed by use of the rear blower motor
resistor (3).
The rear heater-A/C housing must be removed from the vehicle for service of the blower motor and disassembled for service of the A/C evaporator,
heater core, mode-air door and blend-air door.