How do you replace serpentine belt on 2002 Chevy Express?

To replace the serpentine belt on a 2002 Chevy Express, first, locate the belt routing diagram, usually found on a sticker under the hood. Use a wrench or ratchet to relieve tension on the tensioner pulley and remove the old belt. Then, carefully route the new belt according to the diagram, ensuring it sits properly on all pulleys. Finally, recheck the belt alignment, and start the engine to ensure it's functioning correctly.