RAM 2500 Truck 2WD L6-6.7L DSL Turbo (2010)
Housing Assembly HVAC: Description and Operation
DESCRIPTION
All models are equipped with a common HVAC housing assembly that combines A/C and heating capabilities into a single unit mounted behind the
instrument panel in the passenger compartment. The HVAC housing assembly consists of the following:
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HVAC housing - The HVAC housing (1) consists of three pieces that are attached together by molded plastic retaining clips and screws. The
HVAC housing contains the heater core, A/C evaporator and blend-air and mode-air doors, and has mounting provisions for the air-door actuators,
floor console duct (when equipped with center floor console), blower motor, blower motor resistor or power module (depending on the control
application), foam seals and the HVAC wire harness.
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Air inlet housing - The air inlet housing (2) is mounted to the right end of the HVAC housing and contains the recirculation-air door and has
mounting provisions for the recirculation door actuator.
The heating-A/C system is a blend-air type system. The blend-air doors control the amount of conditioned air that is allowed to flow through or around
the heater core. The dual zone heating A/C system uses two blend door actuators while the single zone system uses only one blend door actuator.
The A/C system is designed for the use of a non-CFC, R-134a refrigerant and uses an H-block type A/C expansion valve, evaporator and evaporator
temperature sensor to cool and dehumidify the incoming air prior to blending it with the heated air. The temperature control(s) determines the discharge
air temperature by operating the blend door actuator(s), which moves the blend-air door(s). This allows an almost immediate control of the output air
temperature of the system. The mode door actuators operate the mode-air doors which direct the flow of the conditioned air out the various air outlets,
depending on the mode selected. The recirculation door actuator operates the recirculation-air door which closes off the fresh air intake and recirculates
the air already inside the vehicle. The blower motor controls the velocity of air flowing through the HVAC housing assembly by spinning the blower
wheel within the HVAC housing at the selected speed by use of the blower motor resistor or power module (depending on application), which is located
at the bottom of the HVAC housing. The electric door actuators, blower motor resistor or power module, blower motor and evaporator temperature
sensor are connected to the vehicle electrical system by the HVAC wire harness.
The HVAC housing must be removed from the vehicle for service of the air inlet housing and disassembled for service of the heater core, A/C
evaporator and the blend-air and mode-air doors.
