HVAC Housing: Description
All models are equipped with a common HVAC housing assembly that combines A/C and heating capabilities into a single unit mounted within the passenger compartment. The HVAC housing assembly consists of three separate housings:
- HVAC housing - The HVAC housing (1) is mounted to the dash panel behind the instrument panel and contains the evaporator core and the blower motor resistor block or power model, depending on application. 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, air distribution housing and the HVAC wire harness.
- 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 actuator.
- Air distribution housing - The air distribution housing (3) is mounted to the rear of the HVAC housing and contains the heater core, blend-air door(s) and actuator(s), mode-air doors and actuators and door linkages.
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 A/C evaporator 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(s), which moves the blend-air door(s). This allows an almost immediate control of the output air temperature of the system. The two 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 electric door actuators are connected to the vehicle electrical system by the HVAC wire harness. The blower motor controls the velocity of air flowing through the HVAC housing assembly by spinning the blower wheel within the HVAC housings at the selected speed by use of the blower motor resistor block or power model, depending on application.
The HVAC housing must be removed from the vehicle and disassembled for service of the A/C evaporator. The air distribution housing must be removed from the HVAC housing and disassembled for service of the mode-air and blend-air doors. The air inlet housing must be removed from HVAC housing and disassembled for service of the recirculation-air door.