A/c-Heater System - Automatic Saab 9000 I

A/C SYSTEM SPECIFICATIONS

A/C SYSTEM SPECIFICATIONS

DESCRIPTION

The automatic A/C-heater system maintains the selected temperature inside the vehicle regardless of ambient (outside) air temperature. The A/C-heater control panel monitors and controls air distribution, fan speed, air circulation, A/C compressor, rear window defogger, door mirror heating, and temperature valve.

"Auto" Mode

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

"HEAT" Mode

This mode will direct air through floor and defroster vents. Slight air leakage will occur through instrument panel vents.

"FLOOR" Mode

The "FLOOR" mode will direct air through the floor vents, with a slight air leakage occurring through defroster vents.

"BI-LEVEL" Mode

In this mode, air is directed through instrument panel and floor vents. A slight air leakage will occur through defroster vents. The air supplied through the instrument panel vents should be cooler than the air supplied through the floor vents.

"VENT" Mode

This mode will direct all air through the instrument panel vents. If the difference between selected temperature and temperature inside the vehicle is 9°F (5°C) or greater, the "VENT" function will be automatically selected.

"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 13 minutes. The heating element can be switched off sooner by pressing the defrost button.

The heating for the rear window defogger can also be switched on manually, but will be switched off automatically after 13 minutes. Manual selection of the defrost mode will NOT switch on the rear window defogger.

Recirculated Air Mode

Depressing the recirculated air button will cause the indicator light to come on and the air within the passenger compartment to recirculate. Air recirculation may be used to prevent exhaust fumes from being drawn into the passenger compartment. If air recirculation is selected automatically, the indicator light will come on.

A/C-HEATER CONTROL PANEL

The A/C-heater control panel receives information from 4 sensors and from the push button settings. When the vehicle is started, the system will be switched on automatically and bring the temperature up or down to the selected temperature.

It is possible to override the automatic program by pressing one or more buttons on the A/C-heater system control 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 manual mode has been selected.

In cold weather starting, the automatic program will select the defroster function and a low fan speed. Heating for the rear window defogger will also be switched on. Once the mixed air sensor senses that the temperature has reached 122°F (50°C), the system will direct air through the floor vents and the fan speed will be increased, until the selected temperature has been obtained.

During warm weather starting, the automatic program will select the "VENT" (fresh/air) or "BI-LEVEL" mode (depending on the intensity of the sun), and a high fan speed. The fan speed will gradually decrease as the temperature inside the vehicle approaches the selected temperature.

IN-CAR & BLEND AIR TEMPERATURE SENSORS

The in-car and blend air temperature sensors are thermistors with varying electrical resistance according to temperature. (Scheme 1) The air supply temperature sensor is of the transistor type and is located outside of A/C-heater assembly. An aspirator motor is used in conjunction with the in-car temperature sensor to provide a constant flow of air across the sensor.

SUN LOAD SENSOR

The sun load sensor is a photodiode which senses the sun's intensity. One of the functions of this system, based on the information received from this sensor, is to vary the fan speed according to whether the vehicle's interior is exposed to direct sunlight or shadows.

HEATER CORE & SENSOR

The heater core is located on its side at the bottom of the A/C-heater assembly. There is no heater control valve used in this system, therefore 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 (servomotors). (Scheme 1) The settings of the respective valves are controlled by the A/C-heater control panel.

Scheme 1

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 the amount of refrigerant admitted to the evaporator. The expansion valve regulates refrigerant flow according to 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 the evaporator fins to sense 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 the temperature of the evaporator has risen to 40°F (4.4°C), the A/C compressor will again be engaged.

A/C-HEATER CONTROL PANEL & CIRCUITS

1. Simultaneously press and release "AUTO" and "VENT" buttons on A/C-heater control panel to enter self-diagnostic mode. Self-diagnostic mode will take approximately 40 seconds, as indicated by flashing "88" on digital display.
2. The total number of faults detected in the system will be shown on the digital display. Press "VENT" button once, and the first error code will be displayed.
3. Pressing the "VENT" button repeatedly will display the remaining codes, until all codes are displayed. Press "AUTO" button to exit self-diagnostic mode.

SELF-DIAGNOSTIC ERROR CODES

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 "3" button on A/C-heater control panel to select highest blower motor speed.
2. Set temperature setting to "LO" (displayed 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 A/C SYSTEM PERFORMANCE SPECIFICATIONS table.

A/C SYSTEM PERFORMANCE SPECIFICATIONS

Removal

1. Disconnect negative battery cable. Discharge refrigerant from system using approved refrigerant recovery/recycling equipment. Disconnect hoses from back of A/C compressor. Disconnect compressor clutch electrical lead. Remove plastic cover from right headlight.
2. Loosen belt tensioner pulley nuts to loosen compressor drive belt. Remove belt tensioner pulley from compressor and allow it to rest underneath coolant expansion tank hose. Remove A/C compressor bolts and heat shield. Carefully remove compressor from vehicle.

Installation

1. To install, reverse removal procedure. Tighten 2 front compressor bolts to 15 ft. Lbs. (20 N.m). (Scheme 2) Next tighten the rear compressor bolts to same specification. Finally, tighten the 2 remaining bolts to 29 ft. Lbs. (39 N.m).
2. Tighten belt tensioner pulley and check drive belt tension. Tighten discharge hose to 22-26 ft. Lbs. (30-35 N.m) and suction hose to 26-30 ft. Lbs. (35-40 N.m). Check A/C-heater system for proper operation.

Scheme 2

Removal & Installation

Disconnect negative battery cable. Discharge refrigerant from system using approved refrigerant recovery/recycling equipment. Remove evaporator cover. Unplug connector and remove anti-frost thermostat. (Scheme 4) To install, reverse removal procedure. Make sure capillary tube bottoms inside evaporator.

1. Disconnect negative battery cable. Remove hood and wiper arms. Remove covers from windshield wiper motor and evaporator. Unplug fan control unit connector.
2. Remove seal from false bulkhead panel and lift out signal converter. Remove false bulkhead panel. Remove bolts and place electronic ignition control unit out of way. Remove 4 screws and lead-through panel from false bulkhead.
3. Cut wiring harness tie strap, unplug connectors, and remove complete wiper assembly. Drain cooling system. Remove rubber grommets for coolant hoses. Disconnect quick-release couplings for coolant hoses at heater core.
4. Remove screws and push vacuum pump for cruise control system out of way. Remove evaporator screws and the clips for the refrigerant hoses. Remove lock washer and disconnect cable from temperature valve.
5. Remove engine bracket from right, rear corner of engine compartment. Remove nut from rear engine mount. Attach engine sling to rear lift hook on engine and carefully tilt engine forward.
6. Carefully lift evaporator and remove complete blower motor assembly by releasing clips on either side and twisting assembly diagonally upwards. Remove 4 clips and screws holding assembly together. Separate assembly and remove screw securing blower motor. (Scheme 3)
7. To install, reverse removal procedure. Hook top edge of blower motor assembly over A/C-heater unit and press unit into place, making sure clips are properly engaged. Check that seal and drain pipe from the evaporator are correctly positioned.

Scheme 3

Discharge refrigerant from system using approved refrigerant recovery/recycling equipment. Remove front spoiler and grille. Disconnect condenser fittings and cap all openings. Remove condenser (auxiliary) cooling fan, if equipped. Remove bolts from beneath condenser and carefully remove condenser from underneath. To install, reverse removal procedure. Check A/C-heater system for proper operation.

1. Remove front spoiler and grille. Remove top bolts from radiator steady bars. Remove center bolts from bottom of radiator crossmember.
2. Loosen headlight cluster screw and ease out light fixture. Remove headlights. Remove bracket and ignition coil assembly. Remove bolts for radiator and cooler assembly.
3. Remove end bolts from top of radiator crossmember. Remove top radiator crossmember, being careful not to damage paint. Remove nut and 2 bolts securing condenser cooling fan. To install, reverse removal procedure.

1. Disconnect negative battery cable. Discharge refrigerant from system using approved refrigerant recovery/recycling equipment. Remove evaporator cover. Remove false bulkhead panel from engine compartment. Remove insulation and clip.
2. Disconnect capillary tube and cap all openings. Disconnect expansion valve fittings. Remove expansion valve. (Scheme 4) To install, reverse removal procedure. Check A/C-heater system for proper operation.

Scheme 4

1. Disconnect negative battery cable. Remove hood and wiper arms. Discharge refrigerant from system using approved refrigerant recovery/recycling equipment. Remove covers from windshield wiper motor and evaporator.
2. Remove seal from false bulkhead panel and lift out signal converter. Remove false bulkhead panel and top stay for oil filler pipe. Remove engine bracket from right, rear corner of engine compartment.
3. Remove nut from rear engine mount. Attach engine sling to rear lift hook on engine and carefully tilt engine forward. Loosen fittings on the inlet side of the receiver-drier and the outlet side of the evaporator.
4. Remove grommet from firewall and remove power steering fluid reservoir. Position reservoir and pipes out of way. Remove cruise control vacuum pump. Unplug connectors for fan control unit, air recirculation valve actuator (servomotor), anti-frost thermostat, and refrigerant pressure switch on receiver-drier.
5. Remove screw securing evaporator assembly. Carefully move evaporator assembly toward center of vehicle lift assembly. With evaporator assembly on bench, remove fresh air filter. (Scheme 4)
6. Remove screw securing receiver-drier and disconnect fitting between receiver-drier and expansion valve. Remove insulation to enable clips securing the sensor probe to be removed.
7. Disconnect capillary tube and expansion valve. Remove anti-frost thermostat. Remove air recirculation valve actuator. Cut through gasket on evaporator case flange. Release fasteners, separate case halves, and remove evaporator core.

1. To install, reverse removal procedure. Ensure evaporator core is placed in inner grooves of evaporator case, outer grooves are for fresh air filter.
2. Make sure anti-frost thermostat is fully seated. Ensure that expansion valve capillary tube makes good contact with evaporator discharge pipe. Wrap insulation around capillary tube. (Scheme 5) Check A/C-heater system for proper operation.

Scheme 5

1. Remove blower motor assembly. (Scheme 3) Drain cooling system. Release quick-disconnect couplings and disconnect hoses from heater core.
2. Lift up evaporator and remove heater core. To install, reverse removal procedure. Use new "O" rings on quick-disconnect couplings. Refill cooling system and check for leaks.

1. Disconnect negative battery cable. Discharge refrigerant from system using approved refrigerant recovery/recycling equipment. Remove evaporator cover. Unplug connector from refrigerant pressure switch. (Scheme 4)
2. Pull away rubber molding and withdraw pipe from grommet. Disconnect refrigerant line fittings. Remove screw securing receiver-drier. Disconnect fitting at expansion valve. Remove receiver-drier. To install, reverse removal procedure. Check A/C-heater system for proper operation.

1. Disconnect negative battery cable. Remove ashtray. Insert screwdriver into ashtray opening and release tabs securing ashtray trim panel. Remove ashtray trim panel.
2. Reach through ashtray opening and push out A/C-heater control panel. Disconnect 25-pin connector and ground lead. Cut wiring harness tie strap and remove A/C-heater control panel. To install, reverse removal procedure.

Disconnect negative battery cable. Remove cruise control vacuum pump and set aside. Remove screws securing air recirculation valve actuator (servomotor). (Scheme 4) Unplug connector and remove actuator. To install, reverse removal procedure.

Note. The actuators are preset at the factory and must NOT be operated before installation.

1. Press Red arrow temperature selector button until "HI" appears on the A/C-heater control panel display. Disconnect negative battery cable.
2. Press glove box hinges inward and allow glove box door to hang freely. Pull glove box courtesy light into glove box. Remove 6 screws and glove box complete with vent (use a screwdriver to carefully ease vent out of dash panel).
3. Remove screws and lower passenger compartment fuse block. Unplug actuator (servomotor) connector. Remove lock washer and disconnect cable from actuator. Remove bracket and actuator assembly. (Scheme 1) To install, reverse removal procedure.

Remove A/C-heater control panel. Remove in-car temperature sensor grille. Using 2 screwdrivers, remove sensor by gently pushing it forward into dashboard. Unplug connector and remove sensor. To install, reverse removal procedure.

Disconnect negative battery cable. Unscrew and remove air intake grille (if equipped). Unplug connector and remove sensor. To install, reverse removal procedure.

1. Disconnect negative battery cable. Press glove box hinges inward and allow glove box door to hang freely. Pull glove box courtesy light into glove box.
2. Remove 6 screws and glove box complete with vent (use a screwdriver to carefully ease vent out of dash panel). Unplug switch and light electrical leads. Pull blend air sensor out of air distribution housing and unplug connector. (Scheme 1) To install, reverse removal procedure.

Disconnect negative battery cable. Ease door trim seals away from "A" pillar. Remove pillar trim and speaker grille. Remove speaker to gain access to sun load sensor connector. Unplug connector and remove sensor. To install, reverse removal procedure.

Scheme 6