The Isuzu FXR uses 9003 and H4651 bulb sizes for high beam headlight applications and 9003 and H4656 bulb sizes for low beam headlight applications. The replacement chart covers 2004 through 2011 vehicle production 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 Isuzu FXR Tilt Cab uses two distinct headlight technologies across its model range, with sealed beam units fitted in 2004-2005 and a dual-filament halogen bulb fitted in 2006-2011.
The 9003 bulb, used in the Tilt Cab from 2006-2011, is a dual-filament halogen type with a P43t base, rated at 12V with a 60W high beam filament and a 55W low beam filament within a single housing.
Because the 9003 handles both high and low beam functions through two separate filaments, the same physical bulb part number appears in both the high beam and low beam positions for the 2006-2011 Tilt Cab.
The H4651 and H4656 are both 4x6-inch rectangular sealed beam units operating at 12V. In sealed beam construction, the filament, reflector, and lens are fused into one unit, so the entire assembly is replaced rather than an individual bulb.
For the 2004-2005 Tilt Cab, the H4651 is specified for the high beam position and the H4656 for the low beam position. Although both share the same 4x6-inch rectangular sealed beam format, they are not interchangeable between positions.
The 9003 bulb conforms to ANSI standards recognized in both the United States and Canada, as do the H4651 and H4656 sealed beam units, placing all three types within the same North American standardization framework.