Subaru GL-10 Headlight Bulb Size

The Subaru GL-10 headlight bulb specifications include 9004 and H4651 sizes for high beam applications, along with 9004, H4652, and H4656 sizes for low beam functions. The replacement chart covers 1985 through 1989 model production 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

If US Type and EU Type show the same value, a direct cross-reference for this bulb is not available or the data is insufficient.

Years	US Type	EU Type	Shop
1985-1989	9004 (With Halogen Capsule Headlamps)	HB1	Check Price
1985-1989	H4651 (With Sealed Beam Headlamps)	H4651	Check Price

Low Beam Headlight

If US Type and EU Type show the same value, a direct cross-reference for this bulb is not available or the data is insufficient.

Years	US Type	EU Type	Shop
1989	9004 (With Halogen Capsule Headlamps)	HB1	Check Price
1989	H4652 (With Sealed Beam Headlamps)	H4652	Check Price
1985-1988	9004 (With Halogen Capsule Headlamps)	HB1	Check Price
1985-1988	H4656 (With Sealed Beam Headlamps)	H4656	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Dual-filament halogen bulb with P29t base. 12V, 65W/45W.	9004	Check Price
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4651	Check Price
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit, variant of H4651. Not a replaceable bulb — the entire unit is replaced. 12V.	H4652	Check Price
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4656	Check Price

Other Locations

Additional Notes

The Subaru GL-10 used two distinct headlamp technologies across the 1985-1989 model years: halogen capsule headlamps and sealed beam headlamps. Each technology requires a different replacement approach and uses entirely different bulb types.
The 9004 is the most frequently cited bulb in these specifications, appearing across all five model years for both high and low beam positions on halogen capsule-equipped GL-10 vehicles. It is a dual-filament halogen bulb with a P29t base, rated at 12V with 65W on high beam and 45W on low beam, and meets ANSI standards for the US and Canadian markets.
Because the 9004 handles both high and low beam functions through its two filaments, a single bulb serves both lighting positions in halogen capsule-equipped GL-10 models, rather than requiring separate bulbs for each function.
GL-10 models fitted with sealed beam headlamps use H-series units, which are not replaceable bulbs. The entire sealed beam unit is replaced as a single assembly when the lamp fails.
On sealed beam GL-10 models, the high beam position uses the H4651 across all five model years, while the low beam position uses the H4652 in 1989 and the H4656 in 1985-1988. The H4651, H4652, and H4656 are all 4x6-inch rectangular sealed beam units operating at 12V and conforming to ANSI standards.
The H4652 and H4651 are noted as variants of the same 4x6-inch rectangular sealed beam format. Despite their close relationship, they occupy different positions within the headlamp assembly and are not interchangeable between high and low beam sockets.
The sealed beam units and the 9004 halogen bulb are not interchangeable with one another, as they represent fundamentally different lamp construction types requiring different housing designs.