Chevrolet El Camino Turn Signal Bulb Size

Additional Notes

• The 1157 bulb is the most widely used type across the Chevrolet El Camino turn signal specifications, appearing in both front and rear positions across the majority of model years covered. It is a dual-filament, 12V, 21W/5W bulb with a BAY15d bayonet base, conforming to the ANSI standard for the US and Canadian markets.
• The BAY15d bayonet base is shared by every bulb type listed in these specifications, including the 1034, 1034NA, 1157, 1157NA, 2057, and 2057NA. This base type uses an offset double-contact design that physically prevents incorrect single-filament bulbs from being seated in the socket.
• The 2057 and 2057NA are rated at 26.9W/8W, making them higher-wattage variants compared to the 1157 and 1034 series, which are rated at 21W/5W. The higher draw filament in the 2057 series produces greater light output for the turn signal function.
• The front turn signal for the Chevrolet El Camino shifted from the 1157 to the 1034NA between 1979 and 1980, then shifted again to the 2057NA between 1982 and 1983. These transitions represent changes in both wattage rating and the inclusion of factory amber glass coating.
• The "NA" suffix on bulb designations such as 1034NA, 1157NA, and 2057NA indicates natural amber glass, meaning the amber color is produced by the glass envelope itself rather than by the lens housing. Substituting a clear equivalent in a position specified for an NA bulb may alter the color output at the lens.
• The 1972 front turn signal is specified as 1157NA rather than the standard 1157 used in surrounding years, making it the only model year in the 1964-1979 front turn signal range to carry the amber glass designation.
• The rear turn signal for the El Camino used the 1157 continuously from 1964 through 1982, representing the longest uninterrupted bulb fitment in the specifications. The rear position then transitioned to the 2057 for 1983-1987.
• The 1034 and 1034NA are described as variants of the 1157 and share the same 21W/5W rating, but they are distinct ANSI part numbers. Despite the shared wattage and base type, the 1034 series and 1157 series are not confirmed as interchangeable within these specifications.
• The 1959 and 1960 model years share identical bulb fitment, using the 1034 in both the front and rear turn signal positions. These are the only two years in the specifications where the front and rear positions use the same non-NA, non-1157 bulb simultaneously.
• The front and rear turn signal positions do not always share the same bulb type within a given model year. For 1980-1982, the front position used the 1034NA while the rear used the 1157, and for 1983-1987, the front used the 2057NA while the rear used the 2057, pairing each position with its respective amber glass variant.