How do you change belt tensioner pulley 1997 aerostar ford van?

To change the belt tensioner pulley on a 1997 Ford Aerostar van, first, disconnect the negative battery terminal for safety. Then, locate the serpentine belt and use a wrench to relieve tension on the tensioner pulley, allowing you to remove the belt. Next, unbolt the old tensioner pulley from the tensioner assembly and replace it with the new pulley. Finally, reattach the serpentine belt and reconnect the battery terminal.