Durango 2WD V8-5.7L Hybrid (2009)
Housing Assembly HVAC: Description and Operation
Front
DESCRIPTION
NOTE: Front single zone system shown. Front dual zone system similar.
All models are equipped with a common HVAC housing (9) that combines A/C and heating capabilities into a single unit mounted within the passenger
compartment.
The heating-A/C system is a blend-air type system. In a blend-air system, blend-air doors (11) are used to control the amount of conditioned air that is
allowed to flow through, or around the heater core (14). The temperature of the discharge air is varied by operating the blend door actuator (4), which
moves the blend-air doors. In the available dual zone system, two blend door actuators and four blend-air doors are used to provide independent
side-to-side temperature control of the discharge air. This design allows an almost immediate control of the output air temperature of the system. The
electric actuators are connected to the vehicle electrical system by the HVAC wire harness (1).
The mode door actuators (12) operate the mode-air doors (10 and 13), which direct the flow of the conditioned air out the various air outlets (depending
on the mode selected). The recirculation door actuator (3), operates the recirculation-air door (2), which closes off the fresh air intake and recirculates
the air already inside the vehicle.
The blower motor (8) controls the velocity of air flowing through the HVAC housing by spinning the blower wheel (6) within the HVAC housing at the
selected speed by use of the blower motor resistor block or power module (7) (depending on application). The A/C system is designed for the use of a
non-CFC, R-134a refrigerant and uses an A/C evaporator (5) to cool and dehumidify the incoming air prior to blending it with the heated air.
The front HVAC housing must be removed from the vehicle and disassembled for service of the A/C evaporator, recirculation-air door, mode-air doors,
blend-air doors and linkage.
