The GMC K15 Suburban headlight bulb specifications include H6024 and H5001 sizes for high beam applications, along with H6024 and H5006 sizes for low beam functions. The replacement chart covers 1967 through 1978 model years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The GMC K15 Suburban used two distinct sealed beam headlight configurations across the 1967-1978 model range. Model years 1967-1972 used a dual-bulb system pairing the H5001 for high beam and the H5006 for low beam, while model years 1973-1978 used the H6024 for both functions.
The H6024 is a 7-inch round sealed beam unit operating at 12V and conforming to ANSI standards recognized in both the United States and Canada. Because it is a sealed beam design, the entire unit is replaced rather than an internal filament or capsule.
The H5001 is a 4-inch square sealed beam unit, also rated at 12V and built to the same ANSI standard. Its square form factor is physically distinct from the round units used in other positions, making cross-position substitution impossible without modification to the housing.
The H5006 is a 5.75-inch round sealed beam unit at 12V. Although it shares a round form with the H6024, the two are different sizes and are not interchangeable despite their similar appearance.
All three bulb types covered by these specifications are sealed beam units, meaning the lens, reflector, and filament are fused into a single glass assembly. Replacement requires removing the entire unit rather than accessing an internal component.
The shift from the H5001/H5006 pairing to the H6024 for both beams between the 1972 and 1973 model years represents a change in both the physical format and the number of distinct bulb types required to service the headlight system.
The H6024 serving dual duty as both high beam and low beam on the 1973-1978 K15 Suburban means a single bulb type covers the full headlight system for those years, whereas the 1967-1972 system required two different sealed beam types to complete the same assembly.
ANSI standardization across all three bulb types means that H6024, H5001, and H5006 units from any manufacturer meeting the ANSI specification are dimensionally and electrically equivalent to one another within their respective designations.