Peterbilt 376 Headlight Bulb Size

Additional Notes

• The Peterbilt 376 (1988-1999) accommodates four distinct headlamp configurations across its production run: two-rectangular, four-rectangular, four-round, and halogen capsule. Each configuration requires its own specific bulb type, and substitutions between configurations are not supported by the specifications.
• The H6054 is a 5x7-inch rectangular sealed beam unit operating at 12V and conforming to ANSI standards for the US and Canadian markets. It serves as both the high beam and low beam source in the two-rectangular headlamp configuration, meaning a single unit type handles both functions on that setup.
• The 9004 is the only replaceable bulb type listed across all years and configurations. It is a dual-filament halogen bulb with a P29t base, rated at 12V with 65W on high beam and 45W on low beam, and it is used exclusively with the halogen capsule headlamp configuration.
• Sealed beam units, which include the H6054, H4651, H4656, H4652, H5001, and H5006, are not serviceable at the bulb level. When one of these units fails, the entire assembly requires replacement rather than an internal component swap.
• The four-rectangular headlamp configuration uses different bulb types for high and low beam functions. The H4651 or H4652 handles the high beam role, while the H4656 or H4652 handles the low beam role depending on the model year, making beam-position accuracy critical when sourcing replacements.
• The H4651, H4652, and H4656 are all 4x6-inch rectangular sealed beam units operating at 12V. The H4652 is noted as a variant of the H4651. Despite their physical similarity, the specifications assign them to distinct beam positions, and they are not listed as interchangeable with one another.
• The four-round headlamp configuration uses the H5001 for high beam and the H5006 for low beam. The H5001 is a 4-inch square sealed beam unit, while the H5006 is a 5.75-inch round sealed beam unit, both at 12V. The physical difference between these two units means they occupy separate positions within the four-lamp assembly.
• The low beam specification for the four-rectangular headlamp configuration on the 1996 Peterbilt 376 lists the H4652, while most other years in that configuration list the H4656. This year-specific variation means the 1996 model year requires separate verification before sourcing a low beam replacement for that headlamp type.