The White/GMC WHR headlight bulb utilizes a 9004 or H6024 size for both high and low beam functions. The replacement chart covers 1989 through 1995 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 White/GMC WHR carries two distinct headlamp system types across the 1989-1995 model years: composite headlamps and sealed beam headlamps. Each system requires a different bulb or unit, and the correct fitment depends entirely on which headlamp type is installed on the vehicle.
The 9004 is a dual-filament halogen bulb operating at 12V with a wattage rating of 65W on the high beam filament and 45W on the low beam filament. Its P29t base is a proprietary connector type, meaning it is not interchangeable with single-filament or differently based halogen bulbs.
Because the 9004 contains both high and low beam filaments within a single bulb, it serves both the High Beam Headlight and Low Beam Headlight positions on WHR models equipped with composite headlamps. A single bulb type covers both functions in that configuration.
The H6024 is a 7-inch round sealed beam unit conforming to ANSI standards for the US and Canadian markets. Unlike the 9004, it is not a replaceable bulb housed within a separate housing; the entire unit functions as both the optical assembly and the light source.
On WHR models fitted with sealed beam headlamps, the H6024 unit also covers both the high and low beam positions, as the sealed beam format integrates both functions into the same round unit across all listed model years.
The 9004 and H6024 are not interchangeable. One is specific to composite headlamp housings and uses a P29t base connector, while the other is a self-contained sealed beam unit with no equivalent socket-based installation. Substituting one for the other is not physically possible without changing the headlamp assembly type.
Both the 9004 and H6024 are classified under ANSI standards applicable to the US and Canadian markets, indicating that both conform to regulated performance and dimensional criteria within those regions.