For the 2021 Nissan Titan, the high-beam headlight uses a 9005 bulb. Low-beam fitment depends on the headlight type: models with halogen headlights use an H11 bulb, while models with LED headlights use an LED low-beam assembly.
Fog-light fitment is listed as H11 LED or H16 LED. Front turn signals use 7444NA, and the front parking light is also 7444NA on models with halogen headlights; models with LED headlights use LED parking lights.
Other notable exterior fitments include 921 reverse lights, with brake-light fitment listed as either 921 or PW16W. The center stop light and license-plate light use LED, while daytime running lights use P13W. Rear turn signals use 3057 bulbs and tail lights use 3057R bulbs. Interior applications include DE3175 for the dome and map lights, 2721 for the glove-box light, and 158 for the step light. Door-mirror and trunk lights are LED.