A/C System

(W 0Air Conditioning, A/C:

WIRING DIAGRAM

Air Conditioning, A/C: Component Location:

COMPONENT LOCATION VIEW

Air Conditioning, A/C: Component ID:

COMPONENT ID
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.

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:
^ 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.

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:
^ 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.

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).