First I would run the engine with the belt removed, just long enough to verify the noise is gone. As an alternative, dribble a little water onto the smooth back side of the belt while the engine is running and the noise is occurring. If the squeal changes, the typical cause is a pulley is turned or tipped a little. That will make the belt walk across it as it goes around it, and that is what causes the squeal. Fraying on one edge is another clue to a pulley problem.
If you look straight down to the upper area of the belt, you should not see it peeking out to the side on one of the lower pulleys. That can be hard to tell, but if the belt is off-center by as little as 1/16", that's more than enough to cause a squeal. Also, the pulleys were painted black originally. Look for any pulley where the worn, shiny area is peeking out due to the belt now running to the side a little. Either that pulley or the one right before it is turned or tipped.
Tipped pulleys are usually idler or tension-er pulleys riding on a bearing. The suspect is less likely to be the power steering pump, generator, or AC compressor.
Wednesday, April 12th, 2017 AT 3:27 PM