1996 Plymouth Voyager squeeks

I have sometimes just changed the belt to get rid of a squeak and that will do it. If not, get a straightedge or two of varying lengths, but whatever fits in the space available across the front of each pulley, then measure along it to the edge of the belt to see if the face of the pulley is parallel to the belt. If one is crooked, see if the component can be adjusted in its bracket to bring it up true.