Chevrolet Caprice Parking Light Bulb Size

Additional Notes

• The Chevrolet Caprice parking light specifications cover model years 1966 through 2017, with six distinct bulb types used across that span: 1157, 1157NA, 1034NA, 2057NA, 3057NA, and 12961.
• The 1157 bulb is the most historically recurring type in these specifications, appearing in the Chevrolet Caprice from 1966-1973. It is an ANSI-standard dual-filament bulb with a BAY15d bayonet base, rated at 12V and 21W/5W, with a clear glass envelope.
• The 1157NA, 1034NA, and 2057NA bulbs all share the BAY15d bayonet base with the 1157, meaning the base fitment is physically the same across these types. However, their wattage ratings differ, which affects light output and electrical load.
• The "NA" suffix on several bulb designations, including 1157NA, 1034NA, 2057NA, and 3057NA, denotes a natural amber glass envelope. This coloring is built into the glass itself rather than applied as a coating, producing the amber output required for parking light regulations in the United States and Canada.
• The 1034NA, used in the Caprice from 1976-1982 (with the exception of 1979), is rated at 12V and 21W/5W, the same wattage as the 1157NA. Despite sharing wattage ratings, the two are distinct ANSI part numbers and are not confirmed as interchangeable within these specifications.
• The 2057NA, specified for the Caprice from 1983-1988, is described as a brighter variant of the 1157. Although it uses the same BAY15d bayonet base, its high-filament draw is rated at 26.9W compared to the 1157's 21W, making it electrically distinct from earlier BAY15d types used in the Caprice.
• The 3057NA, specified for the 1991-1992 Caprice, is a dual-filament wedge bulb of the T25 type, rated at 12V and 27W/7W. Its wedge base differs fundamentally from the BAY15d bayonet base used by the 1157, 1157NA, 1034NA, and 2057NA bulbs, meaning it is not physically interchangeable with those earlier types.
• The 12961 is a Philips-designated miniature wedge bulb of the T10 type with a W2.1x9.5d base, rated at 12V and 5W. It is specified for the Caprice from 2011-2017 and operates at a substantially lower wattage than all other bulb types in these specifications, reflecting a different lamp housing design in that generation.
• The T10 wedge base of the 12961 and the T25 wedge base of the 3057NA are both wedge-type connections, but they are different sizes and are not interchangeable with each other or with any of the BAY15d bayonet-base bulbs in these specifications.
• The 1979 Caprice is specified with the 1157NA rather than the 1034NA used in the surrounding model years of 1976-1978 and 1980-1982, indicating a year-specific fitment that differs from adjacent production years.