Wiring diagram for ACC
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Thread: Wiring diagram for ACC

  1. #1
    Regular Saab Guy
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    Wiring diagram for ACC

    Does anyone out there have access to a wiring diagram for the ACC. My 9000 is a 1998 2.3T, but any year or even an AC wiring diagram may help me find the electrical fault.

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  3. #2
    Motor Mouth
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    Re: Wiring diagram for ACC

    What's the fault?

  4. #3
    Regular Saab Guy
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    Re: Wiring diagram for ACC

    The compressor will not run, and I've done the following;
    I've checked all of the fuses.
    I've had the refridgerant system checked and re-gassed.
    I've checked at the 30A fuse in the engine compartment and there is power to the live side, open circuit to the other.
    I've put 12v to the clutch and the compressor runs OK.
    By my diagnosis either one of the relays is not operating, or I've a fault somewhere else. I'm currently trying to track down a replacement for the main power relay that is in the box under the bonnet, but without a diagram I'm reluctant to try anything else and risk knackering the main control unit.

    Any suggestions?

  5. #4
    Motor Mouth
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    Re: Wiring diagram for ACC

    I hope someone will be along shortly with a wiring diagram.

    In the meantime, there are a couple of things that could stop it working: the pressure switch, which is hiding below and behind the offside headlight, is a dual switch. If the pressure gets too high, it turns on the cooling fan. If it is too low, it stops the compressor working so that it does not run without lubrication. The wiring to the switch is renowned for failing, normally preventing the cooling fan from running by failing on the high presure side, but it could also fail on the low pressure side, and prevent any function. Also, the compressor has a high temperature cut out screwed into the casing, as a back up safety device. If this has failed, the compressor clutch will not engage. This cut out is easy to check, whereas the pressure switch is a bit fiddly to get at.

    See this item for a detailed description.

  6. #5
    Saab Nut
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    Basingstoke, Hampshire, England
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    Re: Wiring diagram for ACC

    try www.townsendimports.com it's a fair bet there'll be something on there for the acc.

    I've just tried to have a look but can't get on to it right now.

    Harvey

  7. #6

    Re: Wiring diagram for ACC

    The following is for a '96, but I think the '98 is the same.

    Here is a diagram.

    Here's the key:

    16 Rheostat, lighting for instruments and controls, on the dashboard between the steering wheel and driver's door.
    22a Fuse board behind the access panel in the glove box.
    36 Motor, ACC ventilation fan, in fan housing between the evaporator casing and heater housing.
    38 Motor, air recirculation flap, on the evaporator casing.
    113 Relay, electrically heated rear window, in main fuse box behind the glove box.
    210 EDU trip computer in the main instrument display panel.
    216 ACC control module, in the centre of the dashboard.
    217 Blended air temperature sensor, under the servo motor unit.
    218 Cabin temperature sensor on the dashboard between the steering wheel and centre console.
    219 Suction fan, cabin temperature sensor, on the dashboard between the steering wheel and centre console.
    220 Speed control, ventilation fan, in the evaporator casing where it joins the fan housing.
    221 Motor, air distribution damper, behind the glove box on the servo motor unit.
    222 Motor, temperature flap, behind the glove box on the servo motor unit.
    223 Solar sensor, on top of the dashboard in the middle.
    230 Distribution terminal (+30 circuit) in main fuse box behind the glove box.
    231 Distribution terminal (+54 circuit), in main fuse box behind the glove box.
    247RL Motor, door fan, in the left-hand rear door.
    247RR Motor, door fan, in the right-hand rear door.
    286 Outside temperature sensor, behind the front spoiler on the left.
    445 (H16-1) Diagnostics test socket, below the steering wheel.

    2-Pin Connectors
    H2-7 Adjacent to ventilation fan motor 36.
    H2-29 In the right-hand rear door beside the fan motor.
    H2-37 In the left-hand rear door beside the fan motor.

    10-Pin Connectors
    H10-4 Behind the glove box on the ACC servo motor unit.
    H10-22 In the right-hand B pillar.
    H10-24 In the left-hand B pillar.
    H10-25 Behind the left-hand headlamp.

    Grounding Points
    G2 Grounding point, battery tray, on the left-hand wheel housing.
    G5 Grounding point, rear seat, under the left-hand part of the seat.
    G8 Grounding point, dashboard, by the left-hand front loudspeaker socket.
    G24 Grounding point, right-hand front seat member.


    How it works:

    GENERAL
    Some cars are equipped with an Automatic Climate Control (ACC ) system. The heating and ventilation system (including A/C) is then controlled automatically so that the desired temperature in the cabin is maintained at all times, regardless of the outside temperature. Air conditioning (A/C) with a recirculation mode is always included in the ACC system.

    The climate control unit has the following functions:
    <ul type="square">[*]Automatic temperature control, including automatic control of recirculation.[*]Rear door fans.[*]Electrically heated rear window.[*]Electrically heated door mirrors.[/list]The A/C compressor can be deactivated by means of the ECON button while the other functions remain under automatic control.

    The system can be switched off with the OFF button. By pressing one of the buttons on the right of the unit, the particular function can be switched on manually. If the button is pressed again, the function returns to the programmed mode.

    Light-emitting diodes show which parts of the ventilation system are active, irrespective of whether the system is on automatic or under manual control.

    To enable the system to achieve the required temperature in the cabin, data is required from a number of sensors, actuator motors, etc.

    DESCRIPTION OF OPERATION
    The climate control unit obtains data from both the control panel and the following sensors:

    Cabin Temperature Sensor 218
    Interior temperature sensor 218 is an NTC resistor which senses the temperature of the cabin air. It is integrated with suction fan 219, which provides an even air flow around the sensor. The sensor is connected via pins 15 and 33 while the suction fan is supplied with 12 V via pin 16.

    Blended Air Temperature Sensor 217
    The blended air temperature sensor is an NTC resistor which senses the temperature immediately after the air-mixing damper. The sensor is connected via pins 14 and 32.

    Solar Sensor 223
    The solar sensor consists of five solar cells arranged in a cube under the black cover. Pulses are sent to the solar sensor from ACC pin 5. Digital pulses are sent to pin 6 of the ACC control module via an amplifier stage.

    Outside Temperature
    The outside temperature is obtained in the form of digital pulses from EDU trip computer 210 applied to pin 18 of the ACC control module.

    Power Supply
    Climate control unit 216 is supplied with current via fuses 17 and 1.

    The unit is always supplied with current directly from the battery via fuse 17. This is the main power supply for the system.

    When the ignition switch is in the Drive position, the unit is also supplied with current via fuse 1. Suction fan 219 for interior temperature sensor 218 starts at the same time.

    Ventilation fan 199 is supplied with current via fuse 6. Pin 31 of the unit is connected to instrument lighting rheostat 16.

    Climate Control Unit 216
    The unit controls the following functions/units:
    <ul type="square">[*]Ventilation fan 36 via speed control 220. Fan speed is controlled steplessly. Pin 17 of the control module supplies the control with 12V. A speed control voltage of 0-5V is supplied via pin 20, where 0V = fan stationary, 5V = maximum speed.[*]Stepping motor 222 for the air-mixing damper which controls the flow of air, directing it through the heat exchanger or bypassing it. The motor is connected to pins 27, 28, 30 and 29.[*]Stepping motor 221 for the air-mixing damper which controls the air flowing through the defroster and/or ventilation outlet. The motor is connected to pins 23, 24, 26 and 25.[*]Servo motor 38 for the air recirculation flap. When the flap is closed, air is admitted from outside and when it is open (recirculation position), air from inside the cabin is used (recirculated). The motor is connected to pins 2 and 21 of the unit.[*]Electrically heated rear window 115 and heating elements 207 in the door mirrors, which are controlled via relay 113. The relay is connected to pin 39.[*]Rear door fans 247RL and 247RR are connected to pins 9 and 10 respectively.[/list]IMPORTANT : The cooling fins on the speed control are live (+12V) when the ignition is switched on. If the cooling fins are grounded, the speed control will be rendered unserviceable.

    FAULT DIAGNOSIS HINTS
    When taking readings and carrying out fault diagnosis, the connector must be unplugged. All readings must be taken on the connector and not on the climate control unit. With the exception of changing bulbs, the unit must not be tampered with in any way.

    Self-Diagnostics
    There is a special self-test program in the climate control unit's microprocessor.

    The program checks certain functions at regular intervals while the car is being driven and an emergency mode will be activated if a fault develops in any of the sensors. Faults detected by the self-diagnostics program are stored as diagnostic trouble codes in the microprocessor's memory. Readouts of diagnostic trouble codes are obtained with an ISAT scan tool.

    Calibration
    The flap actuator motors must be calibrated at the following times:
    <ul type="square">[*]After changing the control panel.[*]After changing the flap motors.[*]If the battery is disconnected within 30 seconds of the ignition having been switched off.[*]If the battery has been fully discharged or if battery positive voltage has been higher than 16 V.[/list]Calibration is carried out either by pressing the AUTO and VENT buttons simultaneously or by means of an ISAT scan tool.

    A self-test is carried out in conjunction with calibration. The total time for calibration and self-testing is 22-50 seconds . The number of faults (0-5), if any, is shown in the display during the first 35 seconds .

    Other Fault Diagnosis

    1. Check that the relevant fuses are intact and supplied with current.
    2. Check the interior temperature sensor's suction fan by allowing a thin piece of paper to be sucked onto the intake.
    3. Check the climate control unit connectors. Clean them by unplugging and plugging them in again.
    4. Check the wiring harness, connectors and ground connections. For checking A/C compressors and radiator fans, refer to Air Conditioning, A/C.


    Hope this helps.
    www.saab9000.com - all you ever wanted to know about the Saab 9000
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  8. #7
    Regular Saab Guy
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    Re: Wiring diagram for ACC

    Thanks Bill.

    However.............

    Firstly, the link to the diagram isn't working this morning, I'll try it later, but if this is the same as on the Townsend site, it does not include the A/C side of things; compressor, pressure switch, and associated relay, fuse, wiring etc. Does anyone have that?

  9. #8

    Re: Wiring diagram for ACC

    Sorry about the link, as my site is down this morning (well, the site is up, but my ISP's service appears to be non-existent).

    It's not the diagram from Townsend, although it's probably from the same original source (Saab workshop manual). Looks like the A/C compressor, etc, is on a different diagram. I'll post that later too, when my site comes back up.
    www.saab9000.com - all you ever wanted to know about the Saab 9000
    www.saabits.com - stuff to help keep Saabs on the road

  10. #9
    Regular Saab Guy
    Join Date
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    Re: Wiring diagram for ACC

    Luckily a new relay has fixed the problem, but I would still be interested in the wiring diagram, for future reference.

  11. #10

    Re: Wiring diagram for ACC

    Here you go, for the sake of completeness.

    Key:

    16 Rheostat, lighting for instruments and controls, on dashboard between the steering wheel and driver's door.
    22a Fuse board behind the access panel in the glove box.
    35 Switch, ventilation fan, on the control panel for heating and ventilation.
    36 Ventilation fan motor, in fan housing between the evaporator casing and heater housing.
    38 Motor, recirculation flap, on the evaporator casing.
    74 Resistor, ventilation fan, in the fan housing frame beside the cable connection.
    75 Distribution block, battery positive, on the battery tray.
    143 Switch, A/C air recirculation, on the dashboard between the centre console and steering wheel.
    149 Main switch, fan, on rear of the control panel for heating and ventilation.
    156 A/C compressor relay in main fuse box in front of the battery.
    159 Distribution terminal (+15 circuit), in main fuse box behind the glove box.
    166 3-stage pressure switch for the radiator fan, on the receiver in front of the right-hand wheel housing.
    169 Switch, A/C, on dashboard between the steering wheel and centre console.
    170 Compressor, A/C, furthest forward on the right above the manifold.
    171 Antifrost thermostat on the evaporator casing below the windscreen on the right-hand side.
    172 Radiator fan, A/C, to the right behind the front grille in front of the condenser.
    210 EDU trip computer in the main instrument display panel.
    216 ACC control module, in the centre of the dashboard.
    231 Distribution terminal (+54 circuit), in main fuse box behind the glove box.
    342a Main fuse box in front of the battery.
    430 Saab Trionic control module, in engine bay on the left-hand side behind the bulkhead partition.
    433 Relay for disengagement of radiator fan, in main fuse box in front of battery.
    510 Motronic M2.8.1 control module, in the engine bay behind the bulkhead partition.
    587 Motronic M5.2 control module, on a bracket under the dashboard.
    589 Saab Trionic OBDII control module, in the engine bay on the left behind the bulkhead partition.

    1-Pin Connector
    H1-1 On the A/C compressor connection furthest forward on the right-hand side, above the manifold.

    2-Pin Connector
    H2-3 To the left behind the front grille beside the left-hand headlamp.

    4-Pin Connector
    H4-12 By the right-hand wheel housing beside the receiver.

    10-Pin Connector
    H10-15 Behind the left-hand headlamp.

    24-Pin Connector
    H24-2 Behind the left-hand headlamp.

    70-Pin Connector
    H70-1 In the engine bay, behind the bulkhead partition.

    Grounding Points
    G2 Grounding point, behind the battery on the left-hand wheel housing.
    G6 Grounding point, negative distribution terminal, in main fuse box 22B behind the glove box.
    G30 Grounding point, on left-hand structural member behind the left-hand headlamp.
    G31 Grounding point, right-hand structural member, behind the right-hand headlamp.

    How it works:

    GENERAL
    All cars with ACC and certain cars with a heating and ventilation system are equipped with air conditioning (A/C).

    The A/C system is switched on and off with A/C switch 169 or from ACC panel 216 via EDU 210. Compressor 170 and auxiliary A/C radiator fan 172 are activated with relay 156.

    The following conditions must be met in order for switch 169 to be supplied with current from fuse 6:

    <ul type="square">[*]Main ventilation fan switch 149 closed, i.e. air distribution control open.[*]Ventilation fan on, i.e. switch 35 in any of positions 1-4.[/list]As soon as switch 169 is depressed, the integrated lamp is supplied with current directly. When the switch is not depressed, the lamp is supplied with current from rheostat 16.

    For relay 156 to operate and start the A/C compressor, the following conditions must be met:

    <ul type="square">[*]Contacts H and L in pressure switch 166 must be closed (normal position).[*]Antifrost thermostat 171 must be closed, i.e. the ambient temperature must be about +6 C (+43 F) at least.[*]The temperature of the coolant must be lower than 119 C (247 F) in a 4-cyl. engine and 116 C (240 F) in a V6 engine. The temperature is measured by the EDU control module.[/list]If these conditions are satisfied, operating current will be supplied from pin 4 of the EDU control module, via pressure switch 166 and antifrost thermostat 171, to the engine management system, which then grounds relay 156. Compressor 170 and radiator fan 172 start.

    When the evaporator temperature drops towards freezing point, the antifrost thermostat opens and the engine management system disconnects relay 156. The compressor and radiator fan stop.

    The temperature of the evaporator starts to rise and when it reaches the antifrost switching point, relay 155 will again be grounded and the compressor and radiator fan will start up once more.

    When the system is cycling, the output cooling effect is less than what the A/C system is capable of producing. High fan speed, high outside temperature and the speed of the car are factors which strongly influence the ability of the system to reach the cycling point.

    DESCRIPTION OF OPERATION
    Pressure Switch 166
    Switches L and H are safety switches to protect against too low and too high refrigerant pressure. They are normally closed but switch L opens if the pressure drops below about 2 bar. At outside temperatures below 0 C (32 F) the pressure will not be higher than this and switch L deactivates the system.

    If the refrigerant pressure exceeds 27 bar, switch H opens and the system is deactivated.

    Antifrost Thermostat 171
    When the temperature of the evaporator drops to 2.0 +/- 1.1 C (35.5 +/-2 F) , the thermostat opens and then closes when the temperature rises to 3 C (5 F) above its opening temperature.

    3-Stage Pressure Switch 166
    The regular radiator fan 37 is controlled via contact M in pressure switch 166. The switch is normally open when the system is switched on. When the refrigerant pressure reaches 16 bar, the switch closes and relay 155 operates, thus starting the fan motor.

    The switch then goes on and off, depending on the degree of cooling. Switch-off occurs at 12 bar.

    For connection of radiator fan 37, see the Coolinq System wiring diagram.

    Engine Management Systems
    To prevent engine speed from dropping when the compressor is engaged, the control module compensates for the increased load by raising the idling speed.

    Trionic
    In the Trionic system, operating current is supplied from antifrost thermostat 171 to pin 59. Control module 430/589 grounds relay 156 via pin 54.

    Motronic M2.8.1
    In the Motronic M2.8.1 system, operating current is supplied from antifrost thermostat 171 to pin 40 of control module 510. Pin 25 of the control module grounds relay 156.

    Motronic M5.2
    In the Motronic M5.2 system, operating current is supplied from antifrost thermostat 171 to pin 59 of control module 587. Pin 54 of the control module grounds relay 156.

    Recirculation Motor
    When switch 143 is pressed, motor 38 turns the air recirculation flap to the recirculation position, i.e. no fresh air is supplied to the cabin. When the switch is released by being pressed again, the motor returns the flap to the fresh air mode.

    The switch is supplied with current via fuse 1. Its integral lamp lights up at full intensity when in the depressed position.

    FAULT DIAGNOSIS HINTS
    In general, the system is supplied with current when the ignition switch is in the Drive position. If no defective component can be found, check the wiring harness, connectors and ground connections.

    A/C Compressor And A/C Radiator fan

    1. Check fuses 11 and 6 and check that current is supplied to the A/C switch and relay 156.

    2. Depress the A/C switch. Check that current is supplied to EDU control module 210 and from there to pressure switch 166. Check that this switch closes under the conditions mentioned. WARNING Refrigerant will spurt out if the pressure switch is removed. Risk of Frostburn And Eye Injuries

    3. Check antifrost thermostat 171. The temperature must be at least +6 C (+43 F) before its contacts will close the circuit.

    4. Check that relay 156 operates and that the relay contacts are supplied with current.

    5. Check that current is supplied to the coil from the terminal block (+15 circuit) and that it is connected to ground in the relevant control module.

    Recirculation

    1. Check that fuse 1 is intact and supplied with current.

    2. Check that current is supplied to terminal 2 of switch 143 when it not depressed (recirculation not activated).

    3. Check that current is supplied to terminal 7 of switch 143 when it is depressed (recirculation activated).


    Hope this is of some use to someone.
    www.saab9000.com - all you ever wanted to know about the Saab 9000
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  12. #11
    Saab Junior
    Join Date
    Sep 2000
    Location
    Fife, Scotland
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    Re: Wiring diagram for ACC

    Thanks Bill, very useful indeed. I am trying to work out whether or not I can "upgrade" my ACCII unit from the '93 Model to the '96 Model (which as you know has completely different internals - 2 pcbs on 93 and one on 96) Thanks to your posts, I now have the 96 wiring diag and already have the one from Tom Townsend. However I am no expert in electronics but logically speaking I thought it might be possible to rewire the 39 pin connector. I have the 96 ACCII unit here already and need to know if it is feasible or not, would you mind having a think about it.

    Cheers Andy

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