Housing, HVAC: Description
All models are equipped with a common Heating, Ventilation and Air Conditioning (HVAC) housing assembly that combines heating and optional A/C capabilities into a single unit mounted within the passenger compartment. The HVAC housing assembly consists of three separate housings:
- HVAC housing - The HVAC housing (3) is mounted to the back of the instrument panel and contains the A/C evaporator (if equipped). The HVAC housing consists of a upper and a lower housing that are attached together and has mounting provisions for the air inlet housing, blower motor and the air distribution housing.
- Air inlet housing - The air inlet housing (1) is mounted to the passenger side end of the HVAC housing. The air inlet housing contains the recirculation-air door and actuator.
- Air distribution housing - The air distribution housing (2) is mounted to the rear of the HVAC housing and contains the heater core, PTC heater unit (when equipped with a diesel engine) and blend and mode-air doors and linkage.
The HVAC system is a blend-air type system. The blend-air door controls the amount of conditioned air that is allowed to flow through, or around, the heater core.
The A/C system is designed for the use of a non-CFC, R-134a refrigerant and uses an A/C evaporator to cool and dehumidify the incoming air prior to blending it with the heated air. The temperature control(s) determines the discharge air temperature(s) by operating the electric 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 actuator operates 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 actuators, blower motor, and the resistor or power module (depending on application) are all connected to the vehicle electrical system by the HVAC wire harness.
The blend-air and mode doors, and linkage are not serviced separately from the air distribution housing. The air inlet housing must be removed from HVAC housing and disassembled for service of the recirculation-air door. The HVAC housing must be removed from the vehicle and disassembled for service of the A/C evaporator.