Chevrolet El Camino Brake Bulb Size

Additional Notes

• The Chevrolet El Camino brake bulb specifications span model years 1959 through 1987, covering three distinct bulb types across that period: the 1034, 1157, and 2057.
• All three bulb types found in these specifications share the BAY15d bayonet base and dual-filament construction, making them members of the same broad bulb family under ANSI standards recognized in both the United States and Canada.
• The dual-filament design in all three types serves two separate brightness levels within a single bulb, which is a common arrangement in brake and tail light applications where one filament handles running light duty and the other handles the brighter brake signal.
• The 1157 is the most widely specified bulb across these records, covering the Chevrolet El Camino from 1964 through 1982, and operates at 12V with a 21W high filament and a 5W low filament.
• The 2057 replaced the 1157 in the El Camino brake application for the 1983-1987 model years. It shares the same BAY15d base and 12V rating but draws 26.9W on the high filament, making it a higher-wattage variant that produces a brighter brake signal output.
• Because the 2057 and 1157 share the BAY15d base, the 2057 is physically interchangeable with the 1157 in terms of socket fitment, though the wattage difference means the two are not electrically identical replacements for one another.
• The 1034 is specified for the 1959-1960 model years and shares the same 12V, 21W/5W rating as the 1157, though it is listed as a distinct variant under ANSI classification.
• Despite the 1034 and 1157 sharing identical voltage and wattage ratings and the same BAY15d base, they carry separate ANSI designations, which can indicate differences in filament positioning or other construction tolerances that affect fitment precision in specific housings.
• The shift from the 1034 to the 1157 between the 1960 and 1964 model years, and later from the 1157 to the 2057 between the 1982 and 1983 model years, represent the two bulb-type transitions recorded across the full span of these specifications.
• All bulb types in these specifications conform to ANSI standards, which defines consistent electrical and physical parameters intended to support cross-manufacturer compatibility within those classifications.