AZHARI had a very good reply for you there. However I just wanted to add something here for you.
If you can identify the engine fan sensor, while the engine is running you can short the two wires that go to the sensor together to force the electromagnatic clutch to engage.
-If the electromagnetic clutch engaged then your problem is the sensor.
- If the electromagnetic did not engage then the electromagnetic clutch is bad.
Or one other way is to turn on the A/C. When A/C is on, the electromagnetic clutch also engages automatically.
- So if A/C is on then the engine fan should be on. If the engine fan is not on while the A/C is on then most likely your electromagnetic ass'y is bad. Not the sensor, because when the A/C is on, the electrical circuit bypasses the sensor.
Good luck