GMC P6000 Headlight Bulb Size

Additional Notes

• The GMC P6000 uses sealed beam headlight units across all listed model years, meaning the entire lens-reflector-filament assembly is replaced as one unit rather than swapping an internal bulb.
• 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 unit in two-rectangular-headlamp configurations on the GMC P6000, covering the 1983-1990 and 1992 model years.
• The H6024 is a 7-inch round sealed beam unit operating at 12V under the same ANSI standard. On the GMC P6000, it functions as both the high beam and low beam in two-round-headlamp configurations for the 1983-1988 model years.
• Four-rectangular-headlamp configurations on the P6000 use two distinct sealed beam types: the H4651 for the high beam position and the H4656 for the low beam position. Both are 4x6-inch rectangular units rated at 12V under ANSI standards.
• Although the H4651 and H4656 share the same physical 4x6-inch rectangular format and voltage rating, they are not interchangeable. Each is designated for a specific beam position, and substituting one for the other in a four-lamp system would place the wrong beam function in the wrong housing.
• For the 1984 model year, the two-round-headlamp configuration is not listed, whereas it is present for 1983 and 1985-1988. The 1984 entries cover only the two-rectangular and four-rectangular configurations.
• The 1992 and 1990 model years list only the H6054 for both high and low beam, with no headlamp-count qualifier noted, indicating a single configuration applied to those years.
• All sealed beam types listed for the GMC P6000 conform to ANSI standards recognized in both the United States and Canada, meaning the physical and electrical specifications are standardized across those markets regardless of the vehicle's production year.