The Hino FF17 high beam headlight uses an H4651 bulb size, while low beam headlight applications require either H4656 or H4652 bulb sizes. The replacement chart covers vehicle production years spanning 1987 to 1991 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 Hino FF17 uses H4651 sealed beam units for the high beam headlight across all listed model years, spanning 1987-1991.
The H4651 is an ANSI-standardized 4x6-inch rectangular sealed beam unit rated at 12V. Because the light source is fused into the lens and reflector as a single assembly, the entire unit is replaced rather than an internal bulb.
The H4656, also an ANSI-standardized 4x6-inch rectangular 12V sealed beam unit, serves as the low beam headlight for the Hino FF17 in 1987 and 1989-1991.
The 1988 model year is the sole exception in the low beam position, where the H4652 replaces the H4656. The H4652 is described as a variant of the H4651 and shares the same 4x6-inch rectangular sealed beam construction and 12V rating.
Because the H4652 is a variant of the H4651 rather than the H4656, the 1988 low beam unit is not interchangeable with the H4656 units used in the surrounding model years, despite occupying the same position.
All three bulb types, H4651, H4656, and H4652, conform to ANSI standards recognized in both the United States and Canada, placing them within a shared North American standardization framework for sealed beam headlights.
The high beam and low beam positions on the FF17 use different sealed beam types, H4651 and H4656 respectively, meaning the two positions are not interchangeable even though both units share the same physical 4x6-inch rectangular format.