The Chevrolet Spectrum high beam and low beam headlight bulb sizes are 9004 and H6054, with both beams utilizing the same bulb size. The replacement chart covers vehicle production years spanning 1985 to 1988.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Chevrolet Spectrum uses two distinct headlight technologies across its model years, with 1985-1986 models fitted with the H6054 sealed beam unit and 1987-1988 models fitted with the 9004 halogen bulb for both high and low beam functions.
The 9004 is a dual-filament halogen bulb, meaning a single bulb serves both the high beam and low beam functions within one housing. It operates on a P29t base at 12V, with a rated output of 65W on high beam and 45W on low beam.
Because the 9004 handles both beam functions in a single unit, the high beam and low beam headlight positions on 1987-1988 Spectrum models share the same bulb size specification.
The H6054 is a 5x7-inch rectangular sealed beam unit rather than a replaceable bulb. The entire assembly is the light source, so when the unit fails, the whole sealed beam is replaced rather than an internal component.
Both the 9004 and H6054 conform to ANSI standards recognized in the United States and Canada, placing them within a regulated performance and sizing framework common to North American automotive lighting.
The H6054 sealed beam units used on 1985-1986 models are not interchangeable with the 9004 halogen bulbs used on 1987-1988 models, as the two systems differ fundamentally in construction, base type, and housing design.
The shift from the H6054 sealed beam to the 9004 halogen format between the 1986 and 1987 Spectrum represents a change in headlight architecture, with the halogen format allowing the lens and housing to remain in place while only the bulb is replaced.