Cooling Fan Controls Symptom Troubleshooting


Symptom Diagnostic procedure Also check for 
Engine overheats 1.
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Inspect the water pump.
Check the thermostat.
Check for the engine coolant leakage (from gaskets, hoses, O-rings, etc.).
Check for dirt, leaves, or insects on radiator and A/C condenser.
Check for damaged or deformed fan shroud.
Check for plugged or deteriorated radiator hoses.
Check the expantion tank cap.
Inspect the fan motors or fan relays.
Check for plugged heater core or hoses.
Check the coolant level.
Check for deteriorated coolant.
Check for a damaged cylinder head gasket. 
 
The radiator fan runs at low speed, but does not run at high speed when the engine coolant temperature is above 100 °C (212 °F) Radiator fan high speed circuit troubleshooting.  
The A/C condenser fan runs at high speed, but the radiator fan does not run with the A/C off, and the radiator fan runs at high speed when the engine coolant temperature is above 100 °C (212 °F) Remove the fan control relay, and test.
  • If the relay is faulty, replace it.
  • If the relay is OK, repair a short in the wire between fan control relay 5P socket terminal No. 1 and A/C condenser fan motor 2P connector terminal No. 1.
 
 
The radiator fan and the A/C condenser fan run at high speed with the ignition switch ON (II), the A/C off and the engine coolant temperature below 100 °C (212 °F) Repair a short in the wire between radiator fan relay 4P socket terminal No. 3 and radiator fan switch (High) 2P connector terminal No. 2.  
The radiator fan and the A/C condenser fan run at low speed with the ignition switch ON (II), the A/C off and the engine coolant temperature below 93 °C (199 °F) Repair a short in the wire between A/C condenser fan relay 4P socket terminal No. 3 and radiator fan switch (Low) 2P connector terminal No. 1.  
The radiator fan and the A/C condenser fan do not run at low speed with the A/C on Radiator and A/C condenser fan low speed circuit troubleshooting.  
The A/C condenser fan does not run at all. The radiator fan does not run at low speed, but it runs at high speed A/C condenser fan high speed circuit troubleshooting.