Harley-Davidson FXSTB Night Train Headlight Bulb Size
Harley-Davidson FXSTB Night Train headlight bulb specifications include 9003 size bulbs for both high and low beam functions. The replacement chart covers 1999 through 2009 production years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Harley-Davidson FXSTB Night Train uses the 9003 bulb size across all documented model years from 1999-2009, covering both the high beam and low beam headlight positions.
The 9003 is an ANSI-standard bulb recognized in the United States and Canada, operating on a 12-volt electrical system with a dual-filament halogen design rated at 60 watts for high beam and 55 watts for low beam.
Because both the high beam and low beam positions on the FXSTB Night Train share the same 9003 specification, a single bulb type serves both functions through its two internal filaments rather than requiring separate bulbs for each beam.
The 9003 bulb uses a P43t base, which is a bayonet-style mount with a 43mm collar. This base type determines physical fitment and is not interchangeable with housings designed for other base configurations such as H4 or H7 sockets without modification.
The 9003 and H4 bulb types share the same dual-filament halogen construction and wattage ratings, though they differ in base design. The 9003 follows ANSI standards while the H4 follows ECE standards, and the two are not direct drop-in replacements for one another despite their functional similarities.