Cooling Fan Control System

A cooling fan control system in which the ECM controls the cooling fan speed in accordance with the engine coolant temperature and the air conditioning operating condition.

The ECM controls the cooling fan speed based on A/C pressure sensor signals and engine coolant temperature sensor signals. The A/C pressure sensor signals are sent from the A/C ECU to the ECM via the CAN. This control is accomplished by operating the 2 fan motors in 2 stages at low speed (series connection) and high speed (parallel connection).

Condenser Fan Motor

Condenser Fan Motor

A/C Pressure Sensor

02SEG16TE

A/C Pressure Sensor

^ Cooling Fan Operation i

02SEG16TE

^ Cooling Fan Operation i

Air Conditioning Operating Condition

Engine Coolant Temperature

Relay Operation

Cooling Fan Motor Connection

Cooling Fan Operation

No.l

No.2

No.S

OFF

Low

OFF

S to 4

OFF

OFF

OFF

High

ON

S to S

ON

Parallel

High

A/C Pressure "Low"

Low

OFF

S to 4

ON

Series

Low

A/C Pressure "High"

Low

ON

S to S

ON

Parallel

High

A/C Pressure "Low"

High

ON

S to S

ON

Parallel

High

A/C Pressure "High"

High

ON

S to S

ON

Parallel

High

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