So Last night after my drive home I heard this clicking noise. I opened the hood and saw a part of the A/C pulley activated. I know it activates thew A/C condenser when the A/C is on, but what other reason would it be on?


Here is a pic of it. Sorry the pic is so big, I tried to resize it in the post an on Photobucket.

 

you running the defroster?? that will do it too

 

It sounds like the clutch and for your sake be extremely careful and keep a very close eye on it. If you smell any burning smell or smoke stop driving it. A seized up clutch will cause it to stop turning all together and burn your belt up and possibly throw scraps of your belt around.

Mine started off with it staying engaged and eventually seized up. Keep an eye on it but for now it should be okay.

To answer your question, no the A/C shouldn't engage without anything other than the A/C being on.

 

Do you mean the defroster as in the rear/mirror defroster or the windshield defroster?

 

Windshield defroster because what you took a picture of is the A/C compressor and when the defroster runs it also runs the compressor to run the evaporator which removes humidity from the air.

 

Okay that makes sense. I had it on WS/Feet so that answers my Q. To anybody with a 4.7: when you get on the throttle does your engine sound like it has a supercharger? Mine makes a whine kind of noise, I think I narrowed it down to the power steering pump?

 

yup if your vents were set to ws(defrost)/feet it will kick on and off so you are ok in that respect

and no i have not noticed a supercharger whine on my truck

 

I would break out the old stethoscope and figure out where it's coming from. Most whines I've seen do either come from the power steering pump or the tensioner pulley but typically the tensioner pulley will give off more of a squeal. Never know though...