Isuzu FVR Headlight Bulb Size

Additional Notes

• The 9003 bulb is a dual-filament halogen type with a P43t base, rated at 12V with filaments drawing 60W on high beam and 55W on low beam. Its dual-filament design allows a single bulb to serve both high and low beam functions within one housing.
• On the Isuzu FVR (Tilt Cab), the 9003 bulb handles both high beam and low beam duties for the 2006-2011 model years, reflecting its dual-filament capability in a single-bulb application.
• The H4651 and H4656 are 4x6-inch rectangular sealed beam units operating at 12V. Unlike the 9003, these are not bulbs with replaceable filaments; the entire sealed unit is replaced when the light fails.
• The H4651 sealed beam serves the high beam position, while the H4656 sealed beam serves the low beam position. The two units are not interchangeable with each other despite sharing the same physical 4x6-inch rectangular form factor.
• All three bulb types, the 9003, H4651, and H4656, conform to ANSI standards applicable in the United States and Canada.
• The H4651 and H4656 sealed beam units are specified across the Heavy Duty trim for 1988-1995, the standard (no trim noted) configuration for 1996-2001, and the Tilt Cab configuration for 2002-2005 on the Isuzu FVR.
• The trim designations present in the specifications, Heavy Duty and Tilt Cab, indicate that bulb fitment on the FVR is tied to specific body or cab configurations rather than model year alone, making trim identification a necessary step before sourcing a replacement unit.