* Faulty radiator fan relay. The radiator fan relay is responsible for supplying power to the radiator fan. If the relay is faulty, it will not be able to send power to the fan, and the fan will not turn on. To test the relay, you can use a multimeter to check for continuity between the relay's terminals. If there is no continuity, the relay is faulty and needs to be replaced.
* Faulty wiring. The wiring that connects the radiator fan to the relay or the power source may be damaged or disconnected. This can prevent power from reaching the fan, and the fan will not turn on. To test the wiring, you can use a multimeter to check for continuity between the fan's connector and the relay or power source. If there is no continuity, the wiring is faulty and needs to be repaired.
* Faulty fan motor. The fan motor itself may be faulty. This can prevent the fan from spinning, even if the relay and wiring are working properly. To test the fan motor, you can apply 12 volts directly to the fan motor's terminals. If the fan does not spin, the motor is faulty and needs to be replaced.
* 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 be sending an incorrect signal to the ECU, which may prevent the ECU from turning on the radiator fan. To test the coolant temperature sensor, you can use a multimeter to check for continuity between the sensor's terminals. If there is no continuity, the sensor is faulty and needs to be replaced
