A/C System

a�0Air Conditioning, A/C:

WIRING DIAGRAM

Air Conditioning, A/C - Component Location:

COMPONENT LOCATION
22A Main fuse board in the dashboard.
35 Ventilation fan switch on heating and ventilation control panel.
36 Ventilation fan, in the centre between the bulkhead partitions.
38 Motor, recirculation flap, on the evaporator housing behind the glove box.
74 Fan resistor, under cabin filter on the left-hand side.
143 Recirculation switch on heating and ventilation control panel.
156 A/C compressor relay on main relay board in the engine bay.
166 3-stage pressure switch for A/C on receiver between front grille and radiator.
169 A/C switch on heating and ventilation control panel.
170 A/C compressor on right-hand side of engine.
171 Antifrost thermostat behind the glove box on the evaporator housing.
216 ACC control module in centre of dashboard.
342A Main fuse board in the engine bay.
419 Pressure switch, high-pressure, A/C, on the receiver between front grille and radiator.
430 Trionic control module behind side trim on right-hand side.
500 ICE control module
LHD:above main relay board in dashboard
RHD:behind main relay board in dashboard
505 Motronic 2.10.3 control module on right-hand side behind the side trim.
510 Motronic 2.8.1 control module on right- hand side behind the side trim.
580 Microswitch, blended air flap, on side of heater housing by the blended air flap's shaft.
581 Electric vacuum valve on heater housing.

33-pin connectors
H33-2 Black connector on bracket below the left-hand A pillar.
H33-4 On the bulkhead partition behind the glove box.

Grounding Points
G30 Grounding point, lefthand structural member behind the battery.
G31 Grounding point, right-hand structural member, in the engine bay on the right- hand side.
G33P Grounding point, connector bracket (Power) below the left-hand A pillar.
G34P Grounding point, control module bracket (Power) below the right-hand A pillar.
G34S Grounding point, control module bracket (Signal) below the right-hand A pillar.

DESCRIPTION OF OPERATION
When switch 35 is in positions 1-4, current will be supplied to the Integrated Central Electronics (ICE) control module via A/C switch 169.

ICE control module 500 monitors the engine coolant temperature and if it is below 126 °C, current is supplied to the engine management system via antifrost thermostat 171 and pressure switch 166. The pressure switch is activated only when the pressure in the A/C system is above 2 bar but below 30 bar.

A/C relay 156 is grounded in the engine management system.

Current is supplied from fuse 5 in the main fuse box in the engine bay via relay 161 to the A/C compressor's overheating cut-out (thermofuse).

If compressor temperature drops below +140 °C, current will be applied to the compressor's electromagnetic clutch.

Microswitch 580 on the side of the heater housing is actuated by the air blender flap's linkage system. When the heater knob is turned to the minimum position, the switch closes and electrically controlled vacuum valve 581 shuts off the vacuum supplied to the heat exchanger valve. This shuts OFF the supply of water to the heat exchanger.


FAULT DIAGNOSIS HINTS
In general, the A/C system will be supplied with current when the ignition switch is in the Drive position.

If a malfunction has occurred and no defective component can be found, check the wiring, connectors and ground connections.