A cooling fan ensures that your engine is working at the proper operating temperature and helps ensure that your car does not overheat. Depending on the model, your car may be equipped with either two small cooling fans or one large fan. For cars with dual fans, one is used to cool the engine and the other cools the air conditioner and radiator. Troubleshooting cooling fans of either type involves the same process. Once a cooling fan is working properly and able to supply proper cooling to your car's engine and air conditioner, you can be assured that you'll have a smoother drive.
Lift the hood of your car, then start the engine. Turn on the air conditioner to its maximum setting. Verify that the cooling fan is indeed turning. If so, you can reasonably assume that the wiring, fuse, fan motor and relay are not defective.
Test that the temperature switch, temperature sensor and the PCM of the fan is energized properly. Switch off the air conditioning while leaving the engine running. Watch the temperature until it reaches the usual operating level. The fan should activate when the coolant reaches about 200 to 230 degrees Celsius. If the fan does not turn on, then it indicates a problem with the control circuit.
Check the resistance of the temperature switch or temperature sensor using a digital multimeter. Check the voltage rating of the relays as well. Verify with the specification sheet of the car cooling circuit that the values you just measured are within the operating range.
Verify that the cooling fan itself is working properly. Remove the wires connecting to the fan and power up the cooling fan by using jumper wires from the car battery going to the cooling fan. The fan should run smoothly with the 12-volt supply. If the fan is spinning slowly or produces a noisy sound, then it is time to change your cooling fan.
