Chevrolet Corvette Turn Signal Bulb Size

Additional Notes

• The Chevrolet Corvette front and rear turn signal specifications span from 1953 to 2013, covering six distinct bulb types across both positions over that period.
• The 4157NA and 5702AK are the two most frequently specified front turn signal bulbs for the Corvette from 1997 onward. Both are dual-filament T25 wedge bulbs rated at 12V, 27W/7W, with the 5702AK being a Sylvania-branded variant of the ANSI 3157 bulb featuring an amber coating, while the 4157NA uses natural amber glass. These two bulbs share the same wattage and base type, though they are not the same part.
• The 3057 is the sole rear turn signal bulb specified for the Corvette from 1997 to 2013. It is a dual-filament T25 wedge bulb rated at 12V, 27W/7W, sharing the same base type and power ratings as the 4157NA and 5702AK used at the front during overlapping years.
• The BAY15d bayonet base is a recurring base type across multiple bulb families in these specifications, including the 1034, 1034NA, 1157, 1157NA, 2057, 2057NA, and 1154. This base features two pins offset at different heights to prevent incorrect installation.
• The 2057NA and 2057 are specified as the front and rear turn signal bulbs respectively for the Corvette from 1984 to 1996. Both use the BAY15d bayonet base and are rated at 12V, 26.9W/8W, making them higher-output variants of the 1157 family. The NA suffix on the front position denotes natural amber glass rather than a clear envelope.
• The 1157 and its variants (1034, 1034NA, 1157NA) dominate the specifications from 1967 through 1983 across both front and rear positions. All share the BAY15d bayonet base and a 12V, 21W/5W rating, with the NA suffix indicating a natural amber glass envelope and the 1034 designation identifying a variant of the 1157 within the same base and wattage family.
• The 1154 is specified for both the front and rear turn signal positions on the 1953-1954 Corvette. Unlike all other bulbs in these specifications, the 1154 is rated for both 6V and 12V operation, reflecting the electrical system standards of that era.
• The "NA" suffix present on several bulb designations, including 4157NA, 2057NA, 1034NA, and 1157NA, indicates a natural amber glass envelope. This coloring is built into the glass itself rather than applied as a coating, which is the method used on the 5702AK.
• Several front turn signal bulb changes occur at specific model years without corresponding changes to the rear. For the 2009 Corvette, the front position uses the 5702AK while the rear continues with the 3057, meaning the front and rear require different bulb types despite both being turn signal applications.
• The dual-filament construction present across all bulbs in these specifications serves two functions within a single housing: the higher-wattage filament operates as the turn signal or brake light, while the lower-wattage filament serves as a running or parking light.