1. Check the fan switch. The fan switch is responsible for turning the fan on and off. If it's faulty, it may not be sending the correct signal to the fan motor, causing it to run continuously. To check the fan switch, you can use a multimeter to test for continuity. If there is no continuity, the switch is faulty and needs to be replaced.
2. Check the relay. The relay is an electrical component that controls the power supply to the fan motor. If the relay is faulty, it may not be able to turn the fan motor off properly. To check the relay, you can use a multimeter to test for continuity. If there is no continuity, the relay is faulty and needs to be replaced.
3. Check the wiring. If the fan switch and relay are both working properly, the problem may be with the wiring. You can check the wiring by visually inspecting it for any damage or loose connections. If you find any damaged or loose wires, repair them and see if that fixes the problem.
4. Check the fan motor itself. If the fan switch, relay, and wiring are all working properly, the problem may be with the fan motor itself. You can test the fan motor by disconnecting it from the power supply and then applying power directly to it. If the fan motor does not run when you apply power directly to it, it is faulty and needs to be replaced.
Here are some additional tips that may be helpful:
* If the fan is stuck on only while the air conditioner is turned on, the problem is likely with the air conditioner relay.
* If the fan is stuck on only when the defroster is turned on, the problem is likely with the defroster relay.
* If the fan is making a loud noise, it may be bearing noise or a problem with the fan blades.
If you are not confident in your ability to diagnose and fix the problem yourself, it is best to take your car to a qualified mechanic.
