Subaru GL high beam and low beam headlight bulbs utilize 9004, H4651, H6054, H4656, and H4652 sizes depending on configuration and model year. The replacement chart covers 1975 through 1989 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 9004 bulb is a dual-filament halogen unit operating at 12V with a 65W high beam filament and a 45W low beam filament, fitted with a P29t base. Because it handles both beam functions through a single bulb, the Subaru GL models from 1985-1989 equipped with halogen capsule headlamps use the same 9004 size for both the high beam and low beam positions.
The H4651, H4652, H4656, and H6054 units are sealed beam headlamps, meaning the lens, reflector, and filament are fused into one assembly. When a filament fails, the entire unit requires replacement rather than just an internal bulb.
The H4651 and H4656 are both 4x6-inch rectangular sealed beam units operating at 12V, and they share the same physical housing format. However, they carry different ANSI designations, which reflects differences in their beam pattern or filament output. Substituting one for the other without confirming the correct designation for the specific position risks incorrect light distribution.
The H4652 is a variant of the H4651 within the same 4x6-inch rectangular sealed beam format. On the Subaru GL, H4652 appears in the low beam position for 1983-1984 four-headlamp configurations and for 1985 sealed beam low beams, while H4651 fills the high beam role in those same configurations.
The H6054 is a 5x7-inch rectangular sealed beam unit, physically larger than the 4x6-inch H465x family. On the Subaru GL, H6054 is used in both the high beam and low beam positions for two-headlamp configurations in 1982-1984, as well as for all headlamp positions in 1980-1981.
The H6024 is a 7-inch round sealed beam unit and represents the earliest headlamp format found in these specifications, appearing on the 1975 Subaru GL for both high and low beam positions.
From 1985-1989, the Subaru GL was offered with either halogen capsule headlamps or sealed beam headlamps, and the correct bulb size depends entirely on which headlamp system is installed. The 9004 applies only to halogen capsule configurations, while the H465x sealed beam units apply to the sealed beam configurations.
In 1982-1984, the two-headlamp configuration uses H6054 units for both beam positions, while the four-headlamp configuration splits duties between H4651 for high beam and either H4652 or H4656 for low beam, depending on the year. These two configurations are not interchangeable in their bulb requirements.