The White/GMC WAH headlight bulb uses 9004 and H6024 sizes for both high and low beam applications. A replacement chart documents bulb specifications across 1990 to 1995 production years.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The White/GMC WAH carries two distinct headlamp system types across the 1990-1995 model years, each requiring a different bulb or unit entirely. Composite headlamp-equipped vehicles use the 9004, while sealed beam headlamp-equipped vehicles use the H6024.
The 9004 is a dual-filament halogen bulb operating at 12V with a wattage rating of 65W on high beam and 45W on low beam. It uses a P29t base and meets ANSI standards applicable in both the United States and Canada.
Because the 9004 handles both high and low beam functions through two separate filaments within a single bulb, it serves both headlamp positions on composite-equipped WAH vehicles without requiring a separate bulb for each function.
The H6024 is a 7-inch round sealed beam unit rather than a replaceable bulb. The entire unit is replaced when it fails, as the lens, reflector, and filament are fused into one assembly. It operates at 12V and also meets ANSI standards for the US and Canadian markets.
The H6024 similarly covers both high and low beam positions on sealed beam-equipped WAH vehicles, mirroring the dual-position role of the 9004 on composite-equipped variants.
The 9004 and H6024 are not interchangeable. One is specific to composite headlamp assemblies and the other to sealed beam housings, and the headlamp system type present on a given vehicle determines which is applicable.