GMC V1500 Suburban Headlight Bulb Size

The GMC V1500 Suburban headlight bulb specifications include high beam sizes H6054, H4701, and H4651, along with low beam sizes H6054, H4703, and H4652 for the front lighting assembly. The replacement chart covers 1987 through 1991 model years with corresponding bulb size data.

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
1989-1991	H6054 (With 2 Headlamps)
1989-1991	H4701 (With 4 Headlamps)
1987-1988	H6054 (With 2 Headlamps)
1987-1988	H4651 (With 4 Headlamps)

Low Beam Headlight

Years	Bulb Size
1989-1991	H6054 (With 2 Headlamps)
1989-1991	H4703 (With 4 Headlamps)
1988	H6054 (With 2 Headlamps)
1988	H4652 (With 4 Headlamps)
1987	H6054 (With 2 Headlamps)
1987	H4656 (With 4 Headlamps)

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.	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

All headlight bulb sizes listed for the GMC V1500 Suburban across 1987-1991 are sealed beam units operating at 12V. In sealed beam construction, the lens, reflector, and filament form a single fused assembly, meaning the entire unit is replaced rather than an internal bulb.
The H6054 is a 5x7-inch rectangular sealed beam conforming to ANSI standards for the US and Canadian markets. It serves as both the high beam and low beam unit on two-headlamp configurations across all model years listed, 1987-1991.
Four-headlamp configurations on the V1500 Suburban use separate dedicated units for high and low beam functions, unlike the two-headlamp setup where the H6054 handles both functions within a single unit.
The H4701 and H4703 are 7-inch round sealed beam units used in four-headlamp configurations for 1989-1991. H4701 is designated for high beam duty and H4703 for low beam duty. Though similar in form, these two units are not interchangeable due to their distinct beam patterns.
For 1987-1988 four-headlamp configurations, the high beam position uses a 4x6-inch rectangular sealed beam. The H4651 fills this role in 1987-1988, while the low beam position transitions across three different units: H4656 in 1987 and H4652 in 1988, both also 4x6-inch rectangular sealed beams.
The H4652 is documented as a variant of the H4651. Both are 4x6-inch rectangular ANSI-standard sealed beams, though their filament configurations differ to suit their respective high and low beam roles, making substitution between them inadvisable.
A notable shift occurs between the 1988 and 1989 model years in four-headlamp configurations. The 4x6-inch rectangular sealed beam units used in 1987-1988 are replaced by 7-inch round units in 1989-1991, representing a change in headlamp housing geometry that affects physical fitment.
All sealed beam types listed, H6054, H4701, H4651, H4703, H4652, and H4656, conform to ANSI standards applicable in both the United States and Canada, indicating consistent regulatory compliance across the specified production years.