Lanos S Hatchback L4-1.6L DOHC D-TEC MFI (1999)
Radiator Cooling Fan Motor: Testing and Inspection
Engine Cooling Fan Circuit Check - Without A/C
Engine Cooling Fan Circuit Check - Without A/C
Circuit Description
The engine cooling fan circuit operates the cooling fan. The cooling fan is controlled by the powertrain control module (PCM)/engine control module
(ECM) based on input from the engine coolant temperature (ECT) sensor. The PCM/ECM controls the low speed cooling fan operation by internally
grounding the PCM/ECM connector terminal C13. This energizes the low speed cooling fan relay and operates the cooling fan at low speed. The low
speed cooling fan operation is achieved by the cooling fan resistor causing a drop in the voltage supplied to the cooling fan. The PCM/ECM controls the
high speed cooling fan operation by internally grounding the PCM/ECM connector terminal C12. This energizes the high speed cooling fan relay,
bypassing the radiator fan resistor This results in high speed cooling fan operation.
Diagnostic Aids
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If the owner complained of an overheating problem, it must be determined if the complaint was due to an actual boil over, or the engine coolant
temperature gauge indicated overheating. If the engine is overheating and the cooling fans are on, the cooling system should be checked.
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If the I/P fuse block fuse F19 or the engine fuse block fuse EF4 become open (blown) immediately after installation, inspect for a short to ground
in the wiring of the appropriate circuit. If the fuses become open (blown) when the cooling fan is to be turned on by the PCM/ECM, suspect a
faulty cooling fan motor.
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The PCM/ECM will turn the cooling fans on at low speed when the coolant temperature is 93 °C (199 °F). The PCM/ECM will turn the cooling
fans off when the coolant temperature is 90 °C (194 °F).
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The PCM/ECM will turn the cooling fans on at high speed when the coolant temperature is 97 °C (207° F). The PCM/ECM will change the
cooling fans from high speed to low speed when the coolant temperature is 94 °C (201 °F)
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The cooling fan circuit can be checked quickly by disconnecting the PCM/ECM 24-pin connector and grounding the connector terminal C13. This
should create low speed cooling fan operation with the ignition ON. By grounding the PCM/ECM connector terminals C13 and C12 and turning
the ignition ON, high speed cooling fan operation should be achieved.
