1995 Ford E-Series Van

I do this to my cars and trucks all the time as I run a logging co. Go get some stuff called Belt Dressing and slop ot all over those belts that are squeaking.
Works just great too. OR you can go the Cheapskate way and pour a bit of motor oil on them it too works just fine but if you put too much on it will be a bit messy. This too works super but with either one you will have to repeat the application now and again. I keep a bottle of old oil in my van just for this. The belts are glazed and that is why they aqueak. So the only permanent qure is to replace the belts