The Big Dog Boxer high beam and low beam headlight bulbs both utilize a 9003 bulb size. The replacement chart covers vehicle production spanning 2001 to 2004.
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 headlight bulb type listed across all model years of the Big Dog Boxer covered in these specifications.
The 9003 is a dual-filament halogen bulb, meaning a single unit contains separate filaments for both high beam and low beam operation.
Because the 9003 serves both the high beam and low beam positions on the Big Dog Boxer (2001-2004), one bulb type handles the full headlight system.
The 9003 operates on a 12-volt electrical system and carries a wattage rating of 60W on the high beam filament and 55W on the low beam filament.
The 9003 uses a P43t base, which is a specific bayonet-style fitting that determines physical socket compatibility.
The 9003 is defined under the ANSI standard and is recognized in both the United States and Canada under that designation.
The 9003 and H4 bulbs share the same physical construction and are functionally interchangeable in many applications, though fitment should be confirmed against the specific socket and housing before substitution.