Chevrolet Citation Tail Light Bulb Size

Additional Notes

• The 1157 bulb is the tail light specification for the Chevrolet Citation across the 1980-1982 model years, while the 1983 model year uses the 2057 bulb instead.
• Both the 1157 and 2057 are dual-filament bulbs, meaning each contains two separate filaments to serve two lighting functions, typically stop and tail, within a single housing.
• Both bulb types share the BAY15d bayonet base, a two-pin offset base design that physically locks the bulb into the socket with a twist.
• The 1157 operates at 12 volts with a wattage draw of 21W on the high filament and 5W on the low filament.
• The 2057 also operates at 12 volts but draws 26.9W on the high filament and 8W on the low filament, making it a higher-output variant relative to the 1157.
• Although the 2057 and 1157 share the same BAY15d base and are physically interchangeable in many sockets, the difference in wattage means the two bulbs are not electrically equivalent, and substituting one for the other may affect brightness output.
• Both bulb types conform to ANSI standards recognized in the United States and Canada, indicating standardized performance and dimensional specifications across manufacturers.
• The shift from the 1157 to the 2057 in the 1983 Citation represents a factory specification change, and using a 1157 in a 1983 socket designed around the 2057 output level would result in a dimmer stop light signal.