Heater and Air Conditioning
A manually controlled single zone type heating air conditioning system is available on this model.HVAC Housing:
All vehicles are equipped with a common heater,ventilation and air conditioning (HVAC) housing. The system combines air conditioning, heating,and ventilating capabilities in a single HVAC housing mounted within the passenger compartment under the instrument panel. The HVAC housing includes:
- Blower motor
- Blower motor resistor block
- Heater core
- A/C evaporator
- Evaporator temperature sensor
- Blend door and actuator
- Mode doors and actuator
- Recirculation door and actuator
Based upon the system and mode selected, conditioned air can exit the HVAC housing through one or a combination of the three main housing outlets: defrost, panel or floor. The defrost outlet is located on the top of the housing, the panel outlet is located on the face of the housing and the floor outlet is located on the bottom of the housing. Once the conditioned air exits the unit housing, it is further directed through molded plastic ducts to the various outlets in the vehicle interior. These outlets and their locations are as follows:
- Defroster Outlet A single large defroster out let is located in the center of the instrument panel top cover, near the base of the windshield.
- Side Window Demister Outlets There are two side window demister outlets, one is located at each outboard end of the instrument panel top cover,near the belt line at the A pillars.
- Panel Outlets There are six panel outlets in the instrument panel, one located near each outboard end of the instrument panel facing the rear of the vehicle and two located at each side of the instrument panel center bezel.
- Front Floor Outlets There are two front floor outlets, one located above each side of the floor panel center tunnel near the dash panel.
The heating and air conditioning system pulls out side (ambient) air through the cowl opening at the base of the windshield, then into the plenum chamber above the heating, ventilation and air conditioning (HVAC) housing and through the evaporator coil.
Air flow can be directed either through or around the heater core. This is done by adjusting the blend door with the temperature control knob on the A/Cheater control located the instrument panel. The air flow can then be directed from the panel, floor and defrost outlets in various combinations using the mode control located on the A/Cheater control. Air flow velocity can be adjusted with the blower speed control located on the A/Cheater control.
NOTE: It is important to keep the air intake opening clear of debris. Leaf particles and other debris that is small enough to pass through the cowl opening screen can accumulate within the HVAC housing.The closed, warm, damp and dark environment created within the housing is ideal for the growth of certain molds, mildews and other fungi. Any accumulation of decaying plant matter provides an additional food source for fungal spores, which enter the housing with the fresh intake air. Excess debris, as well as objectionable odors created by decaying plant matter and growing fungi can be discharged into the passenger compartment during heater A/C operation if the air intake opening is not kept clear of debris.
The heater and air conditioning system is a blend air type systems. In blend air system, a blend door controls the amount of conditioned air that is allowed to flow through, or around, the heater core. A temperature control determines the discharge air temperature by actuating an electric motor, which operates the blend door. This allows an almost immediate control of the output air temperature of the system.
The outside air intake can be shut off by selecting the Recirculation Mode with the mode control. This will operate a electric actuated recirculation air door that closes off the outside fresh air intake and recirculates the air that is already inside the vehicle.
The A/C compressor can be engaged in any mode by pressing the snowflake, A/C on/off button. It can also be engaged by placing the mode control in the mix to defrost positions. This will remove heat and humidity from the air before it is directed through or around the heater core. The mode control on the A/C heater control is used to also direct the conditioned air to the selected system outlets. The mode control uses an electric motor to control the mode doors.
The defroster outlet receives airflow from the HVAC housing through the molded plastic defroster duct, which connects to the HVAC housing defroster outlet. The airflow from the defroster outlets is directed by fixed vanes in the defroster outlet grilles and cannot be adjusted. The defroster outlet grilles are integral to the instrument panel top cover.
The side window demister outlets receive airflow from the HVAC housing through the molded plastic demister ducts. The airflow from the side window demister outlets is directed by fixed vanes in the demister outlet grilles and cannot be adjusted. The side window demister outlet grilles are integral to the instrument panel. The demisters direct air from the HVAC housing through the outlets located on the top corners of the instrument panel. The demisters operate when the mode control is positioned in the floor defrost and defrost only settings. Some air may be noticeable from the demister outlets when the mode control is in the bi-level to floor positions.
The instrument panel outlets receive airflow from the HVAC housing through a molded plastic main panel duct, center panel duct and two end panel ducts. The two end panel ducts direct airflow to the left and right instrument panel outlets, while the center panel duct directs airflow to the four center panel outlets. Each of these outlets can be individually adjusted to direct the flow of air.The floor outlets receive airflow from the HVAC housing through the floor distribution duct. The front floor outlets are integral to the molded plastic floor distribution duct, which is secured to the bottom of the HVAC housing. The floor outlets cannot be adjusted. The A/C system is designed for the use of non CFC,R134a refrigerant. The A/C system has an evaporator coil to cool and dehumidify the incoming air prior to blending it with the heated air. This A/C system uses a fixed A/C orifice tube in the liquid line near the condenser outlet to meter refrigerant flow to the A/C evaporator. To maintain minimum evaporator temperature and prevent evaporator freezing, an evaporator temperature sensor is used. The power train control module (PCM) is programmed to respond to the evaporator temperature sensor input by cycling the A/C compressor clutch as necessary to optimize A/C system performance and to protect the A/C system from evaporator freezing.