How change belt for 2000 Cadillac deville?

To change the serpentine belt on a 2000 Cadillac DeVille, first, ensure the engine is off and cool. Locate the belt routing diagram, usually found under the hood, and then use a wrench or ratchet to relieve tension on the belt by turning the tensioner pulley. Remove the old belt and install the new one, following the routing diagram. Finally, check the tension and ensure everything is correctly aligned before starting the engine.