The Titan's left turn signal, park light, and side lights share one bulb in the main housing of the headlight. The round part works for flashing the turn signals and parking lights, while the small bulb is for side visibility. To reach the lights, loosen and pull back the front fender plastic. Grasp the side marker or turn signal light bulb holder inside the headlight housing by the front wheel opening, twist it counterclockwise to remove it, and just pull the bulb straight out, going in the opposite direction to reinstall. To access tailgate and back-up light assemblies, start by taking out the mounting bolts on the tailgate, then simply pull the entire taillight housing off from the bed. Slide the bulb socket out of its housing, then take off the bulb by turning the holder one full turn in the opposite direction. To change the license plate bulb, slide out the entire housing from its position on the bumper. Pull out the bulb by hand when you have the housing in front of you. To get at and replace the bulbs of the high-mounted brake light, peel off the plastic covers above the roof liner at the back, unscrew the mounting nuts, tease the light assembly out just enough to remove the bulb holders, replace them with new bulbs, then do the reverse to put everything back. The instrument lighting parts are built into the circuit board and are not able to be changed. All you need is a small screwdriver to lift off the cover above the map and dome lights, and then you can replace the light bulbs. When replacing a fog lamp bulb, disconnect the connector hidden at the back of the bumper, twist the bulb counterclockwise from its socket at the bumper, and reverse these steps during installation. Be careful not to come into contact with the new bulb's surface with your hands, as skin oil might make it overheat and die earlier than it should; use rubbing alcohol to tidy up any hand touches.