Peterbilt 365 Headlight Bulb Size

Additional Notes

• The 9003 bulb is a dual-filament halogen unit rated at 12V with a 60W high beam filament and a 55W low beam filament, fitted with a P43t base. Because it carries both filaments in a single capsule, the Peterbilt 365 with halogen capsule headlamps uses the same 9003 bulb for both the high beam and low beam positions across the 2011-2017 model years.
• The 9004 bulb is a dual-filament halogen unit rated at 12V with a 65W high beam filament and a 45W low beam filament, fitted with a P29t base. It is specified for the 2008-2009 Peterbilt 365 equipped with halogen capsule headlamps and serves both beam positions, as the 9003 does on later model years.
• The H4651, H4652, H4656, and H6054 designations are ANSI-standard sealed beam units rather than replaceable bulbs. In each case, the entire sealed unit is replaced rather than an internal filament or capsule.
• The H4651 and H4656 are both 4x6-inch rectangular sealed beam units operating at 12V. H4651 is specified for high beam positions, while H4656 is specified for low beam positions, making the two non-interchangeable despite their shared physical format.
• The H4652 is a 4x6-inch rectangular sealed beam unit described as a variant of the H4651. It appears in the low beam position for the 2009 Peterbilt 365 equipped with four rectangular headlamps, whereas the 2008 model in the same configuration uses the H4656 for that position.
• The H6054 is a 5x7-inch rectangular sealed beam unit, physically larger than the 4x6-inch H465x-series units. It is specified for the 2008-2009 Peterbilt 365 equipped with two rectangular headlamps and covers both beam functions within a single unit.
• The 2008-2009 model years accommodate three distinct headlamp configurations: two rectangular headlamps using H6054, four rectangular headlamps using H465x sealed beams, and halogen capsule headlamps using the 9004. The 2011-2017 model years reduced this to two configurations, replacing the two-rectangular and four-rectangular options with a single sealed beam configuration using H4651 and H4656.
• All bulb and sealed beam types listed across the full 2008-2017 span conform to ANSI standards applicable in both the United States and Canada, and all operate on a 12V electrical system.