Without 2-Speed Radiator Fan
��e Cooling System:
WIRING DIAGRAM
Cooling System With 2 Speed Radiator Fan: Component Location:
COMPONENT LOCATION VIEW
Cooling System With 2 Speed Radiator Fan : Component ID:
COMPONENT ID
1 Battery in the engine bay.
37 Radiator fan motor on left-hand side of radiator.
75 Distribution block, battery, on the battery tray.
81 2-speed radiator fan relay, in main fuse box in front of battery.
155 Radiator fan relay, in main fuse box in front of battery.
159 Distribution terminal (+15 circuit), in main fuse box behind the glove box.
166 Pressure switch for the radiator fan, on the receiver in front of the right-hand wheel housing.
210 EDU, in the main instrument display panel.
231 Distribution terminal (+54 circuit), in main fuse box behind the glove box.
342a Fuse board in main fuse box in front of battery.
367 Resistor beside the radiator fan motor.
419 A/C cooling pressure switch (ME), under the radiator on the right-hand side.
433 Relay for disengagement of radiator fan, in main fuse box in front of battery.
2-Pin Connectors
H2-4 Adjacent to the radiator fan motor.
H2-85 Adjacent to the radiator fan motor.
3-Pin Connector
H3-23 Under the front bumper behind the right-hand fog light.
4-Pin Connector
H4-12 By the right-hand wheel housing beside the receiver.
10-Pin Connectors
H10-15 Behind the left-hand headlamp.
H10-25 Behind the left-hand headlamp.
Grounding Points
G30 Grounding point, left-hand structural member, behind the left-hand headlamp.
G31 Grounding point, right-hand structural member, behind the right-hand headlamp.
DESCRIPTION OF OPERATION
Regardless of the position of the ignition switch, current is supplied to relay 155 via fuse 4 and to relay 81 via max fuse 2.
The radiator fan is controlled by the EDU control module.
The engine coolant temperature is measured by the EDU control module, which controls relay 155.
Single-Speed Radiator Fan
When the temperature reaches about 100 °C (212 °F), relay 155 operates and radiator fan 37 starts. When the temperature drops to about 96 °C (205 °F), the fan stops.
Cars With A/C
When the ignition is switched on, relay 433 operates and connects the A/C system's 3-stage pressure switch 166 in parallel with the EDU control module.
When the intermediate pressure switch closes, relay 155 is grounded via relay 433. Relay 155 operates and the radiator fan starts irrespective of the coolant temperature. When the pressure in the A/C system drops and the intermediate pressure switch opens, the fan will stop unless the coolant temperature is such as to cause the EDU control model to ground relay 155.
Radiator Fan Switch-off Relay 433
To prevent the battery from being drained when the radiator fan continues to run after the engine has been switched off, relay 433 breaks the circuit to the 3-stage pressure switch as soon as the ignition is switched off.
However, the EDU control module can cause relay 155 to operate so that the fan will continue to run at speed 1 (low speed). The time is then limited to 3.5 minutes.
Extra Pressure Switch 419
In certain markets, the A/C system is equipped with an extra pressure switch which controls relay 81. If the refrigerant pressure exceeds 22 bar, the contact will close. This causes relay 81 to operate and engages speed 2 on radiator fan 37.
FAULT DIAGNOSIS HINTS
Single-Speed Radiator Fan
1. Check that fuse 4 is intact and supplied with current.
2. Check that current is supplied to relay 155.
3. Run the engine until it reaches operating temperature and check that the EDU control module is in working order.
4. Check that the relay operates and that the radiator fan is in working order.
5. Check connectors and the wiring harness as well as ground connections.
Cars With A/C
1. Check that fuse 4 is intact and supplied with current.
2. Check that current is supplied to relay 155.
3. Check that current is supplied to relay 433.
4. Switch on the ignition and check that relay 433 operates.
5. Start the engine and check that the intermediate pressure switch in 166 closes and that relay 155 operates.
6. Check that the radiator fan starts
7. Check connectors and the wiring harness as well as ground connections.
8. Run the engine until it reaches operating temperature and check that the EDU control module is in working order.