GMC G3500 Headlight Bulb Size

The GMC G3500 high beam and low beam headlight bulbs utilize H6054, H4701, and H4651 sizes for high beam applications, along with H6054, H4703, and H4652 sizes for low beam applications, with each bulb size corresponding to specific vehicle configurations. The replacement chart covers 1979 through 1996 production years and documents the bulb specifications across this 17-year span.

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
1992-1996	H6054 (With 2 Headlamps)
1992-1996	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
1992-1996	H6054 (With 2 Headlamps)
1992-1996	H4703 (With 4 Headlamps)
1989-1991	H6054 (With 2 Headlamps)
1989-1991	H4652 (With 4 Headlamps)
1988	H6054 (With 2 Headlamps)
1988	H4656 (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 G3500 uses sealed beam headlight units across its entire model range from 1979 through 1996. In sealed beam technology, the lens, reflector, and filament are fused into a single glass unit, meaning the whole assembly is replaced rather than an individual bulb.
The H6054 is the most frequently specified unit across the G3500 range, appearing in both high beam and low beam positions from 1979 through 1996 on two-headlamp configurations. It is a 5x7-inch rectangular sealed beam unit operating at 12V and conforms to ANSI standards applicable in the US and Canada.
The H6024 is a 7-inch round sealed beam unit also rated at 12V under the same ANSI standard. On the GMC G3500, it serves as the sole headlight type for 1985-1987 and also appears on 1980 models equipped with two round headlamps, where it covers both high and low beam functions within a single unit.
The 1980 GMC G3500 is the only model year in these specifications where headlamp shape directly determines bulb fitment. Rectangular two-headlamp configurations use the H6054, while round two-headlamp configurations use the H6024. These two units are not interchangeable due to their differing physical forms.
Four-headlamp configurations on the G3500 introduce a distinct set of sealed beam units for high and low beam positions. The high beam and low beam functions are split across separate dedicated units rather than combined into one, which is the arrangement used in two-headlamp setups with the H6054.
In four-headlamp configurations for 1992-1996, the high beam position uses the H4701 and the low beam position uses the H4703. Both are 7-inch round sealed beam units at 12V, but they are separate ANSI-designated types and are not interchangeable between beam positions.
For 1988-1991 four-headlamp configurations, the high beam position uses 4x6-inch rectangular units (H4651 for 1988-1991), while the low beam position uses related but distinct 4x6-inch rectangular variants (H4656 for 1988 and H4652 for 1989-1991). Despite sharing the same physical format, these units carry different ANSI designations and serve dedicated beam functions.
All sealed beam units specified for the GMC G3500 conform to ANSI standards recognized in both the US and Canada, and all operate at 12V. Physical format alone does not determine interchangeability, as units of the same shape may carry different ANSI designations tied to specific beam functions.