The GMC K35 headlight bulb uses either H6024 or H5001 for high beam and H6024 or H5006 for low beam, with bulb sizes varying across model generations. The replacement chart covers 1968 through 1978 production years and details the corresponding bulb specifications for each interval.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The GMC K35 headlight specifications cover two distinct sealed beam types across the model years listed: H6024 and H5001 for high beam, and H6024 and H5006 for low beam.
The H6024 is a 7-inch round sealed beam unit operating at 12V and conforming to ANSI standards applicable in both the US and Canada. It serves as both the high beam and low beam unit in the 1973-1974 and 1977-1978 model years of the GMC K35.
The H5001 is a 4-inch square sealed beam unit, also rated at 12V and built to the same ANSI standard. It is specified exclusively for the high beam position across the 1968-1972 model years.
The H5006 is a 5.75-inch round sealed beam unit rated at 12V under the same ANSI standard. It is specified for the low beam position across the 1968-1972 model years, pairing with the H5001 high beam unit during that period.
All three bulb types are sealed beam units, meaning the lens, reflector, and filament are fused into a single assembly. Replacement requires substituting the entire unit rather than an internal bulb component.
The H6024, H5001, and H5006 are not interchangeable with one another. Each carries a distinct physical form factor, with the H5001 being square and the H6024 and H5006 both being round but of different sizes.
The 1968-1972 model years of the GMC K35 use a two-bulb system with separate high and low beam units, while the 1973-1974 and 1977-1978 years use a single H6024 unit for both functions.