GMC G2500 Headlight Bulb Size

GMC G2500 high beam and low beam headlight bulbs utilize H6054, H4701, and H4651 sizes for upper beams, while lower beams require H6054, H4703, and H4652 sizes. The replacement chart covers 1979 through 1995 model years with corresponding bulb specifications.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

High Beam Headlight

Years	Bulb Size
1992-1995	H6054 (With 2 Headlamps)
1992-1995	H4701 (With 4 Headlamps)
1988-1991	H6054 (With 2 Headlamps)
1988-1991	H4651 (With 4 Headlamps)
1985-1987	H6024
1981-1984	H6054
1980	H6054 (With 2 Rectangular Headlamps)
1980	H6024 (With 2 Round Headlamps)
1979	H6054

Low Beam Headlight

Years	Bulb Size
1992-1995	H6054 (With 2 Headlamps)
1992-1995	H4703 (With 4 Headlamps)
1990-1991	H6054 (With 2 Headlamps)
1990-1991	H4652 (With 4 Headlamps)
1989	H6054 (With 2 Headlamps)
1989	H4656 (With 4 Headlamps)
1988	H6054 (With 2 Headlamps)
1988	H4652 (With 4 Headlamps)
1985-1987	H6024
1981-1984	H6054
1980	H6054 (With 2 Rectangular Headlamps)
1980	H6024 (With 2 Round Headlamps)
1979	H6054

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). 5x7-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H6054
ANSI standard (US & Canada). 7-inch round sealed beam unit, variant. Not a replaceable bulb — the entire unit is replaced. 12V.	H4701
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4651
ANSI standard (US & Canada). 7-inch round sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H6024
ANSI standard (US & Canada). 7-inch round sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4703
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit, variant of H4651. Not a replaceable bulb — the entire unit is replaced. 12V.	H4652
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4656

Other Locations

Additional Notes

The GMC G2500 headlight specifications cover model years 1979-1995 and reference seven distinct sealed beam bulb types: H6054, H6024, H4701, H4703, H4651, H4652, and H4656. All are ANSI-standardized units rated at 12V and used across both high beam and low beam positions.
Every bulb type listed in these specifications is a sealed beam unit, meaning the lens, reflector, and filament are fused into a single assembly. When a filament fails, the entire unit requires replacement rather than an internal bulb swap.
The H6054 is the most frequently specified bulb across the G2500 range, appearing in both high beam and low beam positions from 1979 through 1995 on two-headlamp configurations, as well as exclusively across 1981-1984. It is a 5x7-inch rectangular sealed beam unit.
The H6024 is a 7-inch round sealed beam unit that serves as the sole headlight type for 1985-1987 and also applies to the two-round-headlamp configuration of the 1980 model year. It functions in both high and low beam roles on those fitments.
On four-headlamp configurations of the GMC G2500, the high beam and low beam positions use separate, non-interchangeable bulb types. For 1992-1995, the high beam uses the H4701 while the low beam uses the H4703, both being 7-inch round sealed beam units of different variants.
Four-headlamp configurations from 1988-1991 use 4x6-inch rectangular sealed beam units. The H4651 and its variant H4652 cover high and low beam positions respectively for 1990-1991, while 1988 follows the same pairing. The 1989 low beam position specifies the H4656 rather than the H4652, making it a unique fitment within that group.
The 1980 model year carries two distinct headlamp configurations with different bulb requirements: the two-rectangular-headlamp setup uses the H6054, while the two-round-headlamp setup uses the H6024. These configurations are not interchangeable with one another.
Because high beam and low beam positions on four-headlamp G2500 configurations use physically different sealed beam units, substituting one position's bulb type for the other is not supported by these specifications, even among units sharing the same physical shape category.