The White/GMC ACL high beam and low beam headlight bulb sizes are 9004, H6024, and H6054, with each bulb size corresponding to specific vehicle configurations. A replacement chart documents bulb specifications across the 1988 to 1995 production range.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The White/GMC ACL uses two distinct headlamp system types across the 1988-1995 model range: composite headlamps and sealed beam headlamps. Each system requires a different bulb or unit, and the two are not interchangeable with one another.
The 9004 is a dual-filament halogen bulb operating at 12V with a high beam output of 65W and a low beam output of 45W. Its P29t base is a single-connector design that carries both filaments, serving both the high and low beam functions within one bulb across all composite headlamp-equipped ACL models from 1988-1995.
Because the 9004 handles both high and low beam functions through its dual filaments, composite headlamp-equipped ACL models from 1988-1995 use the same bulb size for both sub-parts, with no separate bulb required for each beam mode.
Sealed beam headlamp units are self-contained assemblies in which the lens, reflector, and filament form a single sealed unit. When the filament fails, the entire assembly is replaced rather than an individual bulb.
The H6054 is a 5x7-inch rectangular sealed beam unit operating at 12V. It is specified for sealed beam-equipped ACL models from 1989-1993 for both high and low beam positions.
The H6024 is a 7-inch round sealed beam unit operating at 12V. It is specified for sealed beam-equipped ACL models in 1988, 1994, and 1995, representing a different physical form factor than the H6054 and not interchangeable with it.
The H6054 and H6024 sealed beam units differ in shape and size, making them physically incompatible with each other's housings. Installing the wrong sealed beam unit in a given model year would result in an improper fit.
All three bulb and unit types specified for the White/GMC ACL, the 9004, H6024, and H6054, conform to ANSI standards recognized in both the United States and Canada.