Radiator Cooling Fan Control Module: Testing and Inspection

OPERATION
- The engine control module controls the radiator fan motor and condenser fan motor according to the engine coolant temperature and vehicle speed via the power transistors (low speed side and high speed side) in the module.
- If the engine control unit turns ON the low speed side power transistor inside the module, the radiator fan motor relay (Lo) coil operates to send driving power supply (for low speed rotation) from the battery to the radiator fan motor.
If the air conditioner compressor lock controller outputs the air conditioner compressor driving power supply, the current flows to the condenser fan motor relay (Lo).
The condenser fan motor relay (Lo) will operate to send driving power supply (for low speed rotation) from the battery to the condenser fan motor.
If the engine control module turns ON the high speed side power transistor inside the unit, the radiator fan motor relay (Hi) and condenser fan motor relay (Hi) will operate to send the driving power supply (for high speed rotation) to the radiator fan motor and condenser fan motor.




INSPECTION

Using Scan Tool




HARNESS INSPECTION

Measure input voltage applied to ECM.
- ECM connector: Disconnected
- Ignition switch: ON
Voltage: Battery positive voltage
OK: STOP
NG: Check the fan motor relay circuit