- Faulty coolant temperature sensor: The coolant temperature sensor is responsible for sending a signal to the engine control unit (ECU) indicating the engine's temperature. If the sensor is faulty, it may send an incorrect signal to the ECU, causing the radiator fans to stay on continuously.
- Faulty fan switch: The fan switch is responsible for turning the radiator fans on and off based on the engine's temperature. If the fan switch is faulty, it may not turn off the radiator fans when they are no longer needed.
- Faulty ECU: The ECU is responsible for controlling various electrical components in the vehicle, including the radiator fans. If the ECU is faulty, it may not be able to properly control the radiator fans, causing them to stay on continuously.
- Electrical short circuit: A short circuit in the wiring harness that supplies power to the radiator fans can cause them to stay on continuously.
Inspection Procedure:
1. Check the coolant level in the radiator and ensure it is between the "MAX" and "MIN" level indicated on the reservoir.
2. Inspect the wiring harness that supplies power to the radiator fans for any signs of damage or short circuits.
3. Test the coolant temperature sensor and fan switch using a multimeter to ensure proper functionality.
4. Check the ECU for any fault codes related to the radiator fans and address any issues accordingly.
5. Verify the operation of the radiator fans by turning on the engine and allowing it to reach normal operating temperature. The radiator fans should turn on when the engine reaches a certain temperature and turn off when the engine cools down.
Note: If the radiator fans still do not shut off after following the recommended inspection procedure, it is advisable to seek the assistance of a professional automotive technician or a Toyota service center for further diagnosis and repair.
