Chevrolet G-Van brake bulb sizes include 2057, 1157, and 198 specifications, with the center high mount stop light requiring a 921 bulb size. The replacement chart covers vehicle production years spanning 1975 to 1995.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Chevrolet G-Van uses the 2057 bulb as its brake light across the 1983-1995 model years, making it the most frequently specified bulb in these brake light specifications.
The 2057 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with filaments drawing 26.9W and 8W respectively, where the higher-wattage filament serves the stop light function and the lower-wattage filament serves the tail light function.
The 1157 bulb was specified for the G-Van brake light across the 1978-1982 model years. It shares the same BAY15d bayonet base as the 2057 but operates at lower wattages of 21W and 5W.
Because the 2057 and 1157 share the BAY15d bayonet base, they are physically interchangeable in the socket, though their wattage outputs differ. The 2057 produces a brighter stop light signal than the 1157.
The 1975-1977 G-Van brake light used the 198 bulb, a miniature wedge type rated at only 12V and 2W, which is a single-filament design distinct from the dual-filament bulbs used in later model years.
The 198 and the 2057 or 1157 bulbs are not interchangeable, as the 198 uses a wedge base while the later bulbs use a BAY15d bayonet base.
The Center High Mount Stop Light (CHMSL) on the G-Van uses the 921 bulb across the 1988-1995 model years. The 921 is a single-filament wedge bulb rated at 12V and 16W.
The 921 wedge base is not compatible with the BAY15d bayonet base used by the 2057 and 1157 bulbs, meaning the CHMSL and the main brake light positions require separate bulb types.
All four bulb types specified across these G-Van brake light positions conform to ANSI standards applicable in both the United States and Canada.
The G-Van brake light specification reflects three distinct bulb transitions across its production span: the 198 wedge type in 1975-1977, the 1157 dual-filament bayonet type in 1978-1982, and the brighter 2057 dual-filament bayonet type from 1983 onward.