Chevrolet C70 Tail Light Bulb Size

Additional Notes

• The 1157 is the dominant tail light bulb across the Chevrolet C70 specifications, appearing in eleven of the twelve model years listed, spanning 1960-1961 and 1979-1983 and 1985-1988.
• The 1157 is a dual-filament bulb operating at 12 volts with a 21W high filament and a 5W low filament, which allows it to serve both brake/turn signal and running light functions from a single unit.
• The BAY15d bayonet base on the 1157 features two offset pins at different heights, a design that prevents incorrect insertion and ensures consistent filament alignment within the socket.
• The 1984 Chevrolet C70 is the sole model year in these specifications to use the 2057 bulb rather than the 1157.
• The 2057 shares the same BAY15d bayonet base and 12-volt operating voltage as the 1157 but draws more power, rated at 26.9W on the high filament and 8W on the low filament.
• Because the 1157 and 2057 share the same BAY15d base, the 2057 is physically interchangeable with the 1157 socket, though the two bulbs differ in wattage output.
• Both the 1157 and 2057 are classified under ANSI standards and are recognized in both the United States and Canada, indicating standardized production tolerances across manufacturers.
• The higher wattage of the 2057 relative to the 1157 means that substituting a 2057 into a socket designed around 1157 power draw could affect the electrical load on the circuit.