I have a 2001 ram 1500 off road edition. Recently I was hearing a squeakin/chirping noise so I replaced my belt and tensioner no luck. Then I replaced the idler pulley still no luck and last week I replaced the fan clutch still no luck! But I have noticed when the truck gets to running temperature it goes away. Does anyone have a answer?

 

Take off the belt, and spin the remaining pulleys by hand. See if anything doesn't feel quite right.

 

It's the new belt and old pulleys. The old belt polishes the pulleys so you will hear some kind of noise from them. You can try some emery cloth to take some of the shine off them that should take care of it. Lot of work though, I just left mine make noise until it wore in now it's quiet.

 

Mine does the same thing in the morning. The colder the more it does it, until it warms up.
From what I can tell in my case might be the AC clutch pulley when I turn on the AC it goes away.