The GMC FC100 uses an H6006 bulb size for both high beam and low beam headlight applications. The replacement chart covers vehicle production spanning 1950 to 1952.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The H6006 is the sole bulb type listed across all headlight positions in the GMC FC100 specifications, covering both high beam and low beam functions for the 1950-1952 model years.
The H6006 is a 5x7-inch rectangular sealed beam unit operating at 12 volts, conforming to ANSI standards recognized in both the United States and Canada.
A sealed beam unit integrates the filament, reflector, and lens into a single non-serviceable assembly, meaning the entire unit requires replacement rather than an internal bulb component.
The H6006 specification applies identically to both the high beam and low beam headlight positions, indicating the FC100 used a dual-function or interchangeable sealed beam arrangement across those roles.
Because the H6006 is a standardized ANSI unit, physical fitment across compliant housings of the same size class is generally consistent, though electrical compatibility with the vehicle's 12-volt system remains a relevant consideration.