i don't get the fan cluth thing? my fan turns all the time , so what does it the specail clutces do? do they go bad? how :iamwithst do u know

They are supposed to spin all the time but when the truck starts to run hot you should hear the fan roar. Or first thing in the morning you normally hear them roar. All they do is let the engine spin faster than the fan for fuel mileage and power, but is there in case the motor needs more airflow for cooling it can kick in and make the fan turn at a speed closer to the speed the engine is turnng to draw more air.

cool okay now i get it, how does one when it goes bad

If you are running hot and not hearing the fan roar. Or I have seen some really bad ones that I could stop the fan with my hand because they were spinning so slow. I don't stick my hands in fans. It was just I popped the hood of a car that was running real warm and you could count the blades as it was idling it was spnning so slow.

sometimes that also get stuck 'on'. Always roaring away no matter what.