2002 Taurus A/C, 112,000 mi, 6cy 24ohv

You need to narrow down the bad bearing or belt noise. IT can be deceiving. Using a long screwdriver or better yet pry bar with a plastic handle, you can touch the housings close to the bearing in the pullies and place your ear to the plastic handle-right on it and listen for the roughness, the bad one will usually stand out. Also quickly spray belt dressing and see if the noise stops to confirm if it is or not the belt.

IF you believe a bearing is going bad, pull the belt off and spin each pulley feeling for roughness.