Chevrolet C-Series Pickup Headlight Bulb Size

Additional Notes

• The H6054 is a 5x7-inch rectangular sealed beam unit operating at 12V under the ANSI standard. It serves as both the high beam and low beam source in two-headlamp configurations on the Chevrolet C-Series Pickup across 1979-2000, making it the most consistently specified bulb type throughout the entire range covered by these specifications. As a sealed beam unit, the entire assembly is replaced rather than an internal bulb.
• The H6024 is a 7-inch round sealed beam unit rated at 12V under the ANSI standard. It is specified for both high and low beam functions on 1975-1978 models, and also appears as an option on 1979-1980 models equipped with two round headlamps. Like all sealed beam types in these specifications, the full unit is replaced upon failure.
• The 9005 and 9006 are single-filament halogen capsule bulbs specified for 1990-2000 models fitted with halogen capsule headlamps. The 9005 handles the high beam function at 65W with a P20d base, while the 9006 handles the low beam at 55W with a P22d base. Both operate at 12V under the ANSI standard. The two bulbs use different base types and are not interchangeable with each other.
• Four-headlamp configurations on the C-Series Pickup use dedicated sealed beam units that differ by beam function and by model year. The H4701 is specified for high beam use in 1990-1991 four-rectangular-headlamp configurations, while H4703 covers the low beam role in the same fitment. These are 7-inch round sealed beam units and are not interchangeable with each other despite sharing a similar form factor.
• The H4651, H4652, and H4656 are all 4x6-inch rectangular sealed beam units used in four-headlamp configurations from 1981-1986. The H4651 is specified for high beam use across 1981-1986, while H4652 and H4656 serve the low beam position. H4652 is noted as a variant of H4651. The low beam designation shifts from H4656 in 1981-1982 to H4652 in 1983-1985, then back to H4656 in 1986, indicating these units are not universally interchangeable across all years even within the same headlamp count.
• Models from 1992-2000 with sealed beam headlamps use the H6054 for both high and low beam functions, while those with halogen capsule headlamps use the 9005 for high beam and the 9006 for low beam. The two headlamp system types present on the same model year require entirely different replacement parts, and the fitment condition must be confirmed before a replacement unit is selected.
• The 1989 model year is specified only with two-rectangular and four-rectangular headlamp configurations, using H6054 and H4701 for high beam, and H6054 and H4703 for low beam. No halogen capsule option is listed for 1989, unlike the 1990-1991 entries which include all three headlamp system types.
• All sealed beam units across these specifications, including the H6054, H6024, H4701, H4703, H4651, H4652, and H4656, conform to ANSI standards applicable in the US and Canada and operate at 12V. Because the reflector, lens, and filament are fused into a single unit in sealed beam designs, optical performance is fixed at the factory level and cannot be altered by substituting a different internal bulb.