To change the headlight on a 2004 Nissan Sentra, you need to pop the hood. Locate the screws holding the fog lamps and remove them. Remove the clips on the top of the grille and on the side of the fender. Remove bolts from air deflector, lower side of front bumper and remove the bumper fascia. Remove the bumper reinforcement and front bumper side stays. Now you can reach the headlights and replace them.