1998 Jimmy 4wd 4 door

There is an intermittent noise coming from somewhere around the serpentine belt. It comes and goes a few times a minute. It makes noise for maybe 5 to 15 seconds, then stops for a bit. It sound to me like a higher pitched, high speed clicking, almost like a small bearing. I put a screwdriver on the alternator housing, a/c compressor, and on the casting near the pulley between them (these are the three things on top), put my ear to the screwdriver handle, and couldn't hear the noise. I'm not sure if it's coming from the tensioner pulley, from something down below, or maybe from the radiator fan.

What is the best way to isolate this noise, any tips or tricks?

Does replacing the serpentine belt typically stop these noises?

Should the tensioner pulley be tightened somehow?

I'm hesitant to spray belt dressing in there--mechanic didn't like that in the past.

Thanks!