ELECTRICAL FAN CONTROL OPERATION


BHE014000140T47

• When the operation conditions are met for each function, the PCM sends an operation signal to cooling fan relay No.1 or No.2/No.3 to operate the cooling fan motors.

• The rotation speed of the cooling fan motor is switched between two levels according to a combination of the cooling fan relays.

• When only cooling fan relay No.1 is on, the rotation speed is low and when in addition to No.1, No.2 and No.3 are on, rotation speed is high.

Operation Conditions

Function

Operation condition

Cooling fan motor

Cooling fan relay

No.1

No.2

No.1

No.2/No.3

Regular-driving cooling
ECT: Less than 97°C {206.6°F}
Stop
OFF
OFF
ECT: 97°C {206.6°F} or more
Low speed rotation
ON
OFF
• When all the following conditions are met:
– ECT: 97°C {206.6°F} or more
– During fuel cut at deceleration
Low speed rotation
ON
OFF
A/C amplifier (A/C switch): ON
Low speed rotation
ON
OFF
ECT: 101°C {213.8°F} or more
High speed rotation
ON
• When all the following conditions are met:
– ECT: 101°C {213.8°F} or less
– A/C amplifier (A/C switch): ON
– Refrigerant pressure switch (medium-pressure switch): ON
High speed rotation
ON
After-cooling
• When all the following conditions are met:
– Ignition switch: OFF
– Drive-by-wire relay: OFF
– Metering oil pump: Other than during ignition switch off mode
– Engine compartment temperature high.
High speed rotation
ON
• When all the following conditions are met:
– Ignition switch: OFF
– Drive-by-wire relay: OFF
– Metering oil pump: Other than during ignition switch off mode
– ECT: 110°C {230°F} or more
High speed rotation
ON
Forced drive
During test mode (during test mode with WDS) when the AP is depressed.
High speed rotation
ON
Fail safe
When a failure occurs in the ECT sensor.
High speed rotation
ON

1
B+
2
Main relay
3
Cooling fan relay No1.
4
Cooling fan relay No.2
5
Cooling fan relay No.3
6
Cooling fan motor No1.
7
Cooling fan motor No.2
8
To PCM