Chevrolet C-Series Pickup Tail Light Bulb Size

Additional Notes

• The Chevrolet C-Series Pickup tail light specifications span model years 1975 through 2000, with three distinct bulb types appearing across that range: the 3057, 1157, 2057, and 198.
• The 3057 is the most frequently specified tail light bulb across the covered model years, appearing in 1990-1992, 1994-1995, and 1999-2000.
• The 3057 is a dual-filament T25 wedge bulb rated at 12V with a 27W high filament and 7W low filament, conforming to ANSI standards for the US and Canadian markets.
• The 1157 uses a BAY15d bayonet base and carries a 12V, 21W/5W dual-filament configuration, also under ANSI standardization.
• The 2057 shares the BAY15d bayonet base with the 1157 and operates at 12V, but draws 26.9W on its high filament and 8W on its low filament, making it a higher-output variant of the same base type.
• Because the 2057 and 1157 share the BAY15d bayonet base, physical fitment between the two is possible, but their differing wattage ratings means they are not electrically identical and should not be treated as direct substitutes.
• The 198 is a miniature T5 wedge bulb rated at only 12V and 2W, a single-filament low-output type specified for the Chevrolet C-Series Pickup (1975-1978) tail light position.
• The 3057 wedge base and the 198 wedge base are both wedge-type fittings, but their T25 and T5 designations indicate substantially different physical sizes, making them incompatible with each other's sockets.
• The 3057 and the 1157 are both dual-filament bulbs operating at 12V, but they use different base types, a wedge base versus a BAY15d bayonet base, which prevents interchangeability despite their similar electrical roles.
• Model years 1993 and 1996-1998 share the 1157 specification, while the surrounding years in those periods use the 3057, indicating that the socket type in the tail light assembly changed at least twice within the 1990s production run.