A/c-Heater System - Automatic: Other Saab 9000 I рестайлинг

AUTO Mode

The LED indicator beside the AUTO button will come on, and the other indicator lights will show fan speed and air distribution settings selected automatically by the system. System will also automatically select heating for the rear window defogger, door mirrors and/or air recirculation mode. The digital display will show the selected air temperature.

ECON Mode

If the economy mode is selected, the indicator light will come on, and the A/C compressor will not engage. If the temperature of the ambient (outside) air exceeds 81°F (27°C), air circulation will also be selected. All other functions will operate in automatic mode.

Defrost Mode

In this mode, air is directed through defroster vents. A slight air leakage will occur through floor vents. When this button is pressed, the rear window defogger and door mirror heating elements will be switched on, in addition to the functions selected automatically by the system.

Heating for the rear window defogger and door mirrors will be switched on automatically if the system selects the defrost mode when in automatic mode. Heating will be switched off automatically after 10-11 minutes. The heating element can be switched off sooner by pressing the defrost button.

The fans in the rear doors are controlled automatically and runs at the same speed as the main fan. The fans can also be switched on manually.

Recirculated Air Mode

Depressing the recirculated air button will cause the indicator light to come on, and the air within the passenger compartment will be recirculated. Air recirculation is controlled automatically, but can also be selected or cancelled manually. Air recirculation does not change the quality of air significantly.

Floor Air Mode

Mode allows maximum flow of air through all floor vents and a small amount of air through the defroster vents. Panel/Floor Air Mode

In this mode, air flows through the panel vents and front and rear floor vents. A small amount air will also be directed through the defroster vents.

Panel Air Mode

All panel vents fully open.

AUTOMATIC CLIMATE CONTROL (ACC) PANEL

ACC panel (control unit) receives information from 4 sensors and push-button settings. When vehicle is started, system will be switched on automatically, and the temperature will be brought up or down to the selected temperature.

It is possible to override the automatic program by pressing one or more buttons on the ACC panel. The system will then lock in on the selected mode, but the remaining modes will still be controlled automatically. The AUTO indicator light will go out as soon as ECON or OFF mode has been selected.

In cold weather starting, the automatic program will automatically select rear window and door window heating, defroster setting, maximum heat and low fan speed. Once supply air is warm enough, air will be distributed through the floor vents, and fan speed will be increased. As in-car temperature approaches the selected temperature, the fan speed and heat supplied will automatically be reduced gradually to a suitable level.

In warm weather starting, the automatic program will initially directs fresh air through the panel vents at high fan speed, and then switches on A/C compressor (unless ECON mode has been selected). Air recirculation will be selected after about one minute if the ambient air temperature is greater than 77°F (25°C) or the system selects the FLOOR/PANEL or PANEL settings. As in-car temperature approaches the selected temperature, fan speed will be reduced automatically to a suitable level. (Scheme 8)

Scheme 8

BLEND-AIR TEMPERATURE SENSOR

The blend-air temperature sensor is a rod thermistor, which has a negative temperature coefficient. The electrical resistance of the sensor decreases with increasing temperature. The sensor is located inside the right side defroster duct. (Scheme 9)

SUN SENSOR

The sun sensor is a photo diode that transforms sunlight into a voltage signal. The ACC unit computes the angle of the sun relative to the car, the altitude and intensity of the sun. Based on the information received from this sensor, the ACC unit varies the fan speed depending on whether the vehicle's interior is exposed to direct sunlight or shadows.

HEATER CORE & SENSOR

The heater core is located at the bottom of the A/C-heater assembly, on its side. There is no heater control valve used in this system, so the heater core is always warm. A heater core sensor is used to sense the temperature of the air leaving the heater core.

ACTUATORS

The temperature valve, air distribution valve and air recirculation valve are all operated by electrical actuators (stepper motors). (Scheme 9) The settings of the respective valves are controlled by the ACC unit. If a motors has been replaced, ACC system must be recalibrated. See CALIBRATION under TROUBLE SHOOTING.

Scheme 9

EVAPORATOR & CONDENSER

The fin-type evaporator is fitted with a refrigerant manifold. The condenser is made out of aluminum and cooling tubes arranged in a serpentine configuration.

A mechanical safety valve is fitted in the hose running from the condenser outlet. If system pressure rises above 441 psi (31 kg/cm 2 ), the valve opens. The valve closes as soon as pressure falls to 391 psi (27 kg/cm 2 ).

RECEIVER-DRIER

The receiver-drier is mounted on top of the evaporator. The receiver-drier stores refrigerant and a desiccant. A sight glass is fitted to the receiver-drier to give a visual indication of refrigerant charge. A refrigerant pressure switch is also fitted to the receiver-drier.

EXPANSION VALVE

The expansion valve regulates amount of refrigerant admitted to the evaporator. The expansion valve regulates refrigerant flow based on the temperature at the temperature sensor located in the evaporator outlet pipe.

ANTI-FROST THERMOSTAT

The anti-frost thermostat is fitted on top of the evaporator. Its function is to prevent the formation of frost or ice on the evaporator cooling fins. A capillary tube is fitted between evaporator fins to monitor the temperature.

If evaporator temperature falls to 35°F (1.7°C), the thermostat will break the power supply to the A/C compressor. Once evaporator temperature has risen to 40°F (4.4°C), A/C compressor will again be engaged.

A/C SYSTEM PERFORMANCE

1. Attach manifold gauge set to A/C system. Insert thermometer in center vent of dash panel. Close all passenger compartment doors. Press blower button on ACC control panel to select highest blower motor speed.
2. Set temperature setting to LO (shown on digital display). Manually select air recirculation mode, and press VENT button. Ensure engine is fully warmed and running at 2000 RPM. Compare manifold gauge set/thermometer readings with values in «A/C SYSTEM PERFORMANCE»(ref-13613-S04883050492000122600000) SPECIFICATIONS .

A/C SYSTEM PERFORMANCE SPECIFICATIONS

ACTUATING MOTORS

Note. Each motor is a sealed unit. Replace motor as an assembly.