The Triumph Thunderbird Commander uses 9003 bulb size for both high beam and low beam headlight applications. Replacement chart data covers 2014 through 2016 model years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 9003 bulb is the sole bulb type across all listed positions and years for the Triumph Thunderbird Commander, appearing in both the high beam and low beam headlight positions for 2014 and 2016.
The 9003 is a dual-filament halogen bulb, meaning a single bulb contains two separate filaments: one rated at 60W for high beam output and one at 55W for low beam output.
The 9003 operates on a 12V electrical system, which is standard for passenger vehicles of this type.
The bulb uses a P43t base, a bayonet-style fitting with a 43mm collar. This base type is specific to the 9003 and its international equivalent, the H4, and is not interchangeable with single-filament base types such as P14.5s or P15d.
The 9003 carries ANSI standardization applicable to the United States and Canada. Its functional and physical equivalent in international markets is the H4, though labeling and certification may differ by region.
Because the 9003 serves both the high beam and low beam functions within a single housing on the Thunderbird Commander, the headlight assembly does not require separate bulbs for each beam mode.