Chevrolet R/V Series front and rear turn signal bulbs utilize 2357NA, 3057NA, 2057NA, 3057, and 2057 bulb sizes across multiple applications. The replacement chart covers 1987 through 1991 vehicle production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Chevrolet R/V Series front turn signal uses the 2357NA bulb for model years 1988-1991. This bulb follows the ANSI standard recognized in both the United States and Canada, operates at 12 volts, and carries a dual-filament design with a BAY15d bayonet base and natural amber glass, rated at 26.9W for the high-filament and 8W for the low-filament.
The 1987 R/V Series front turn signal fitment splits into two distinct bulb sizes depending on headlamp configuration. Trucks equipped with two headlamps use the 3057NA, while those equipped with four headlamps use the 2057NA. These two bulbs are not interchangeable with each other despite sharing the same wattage ratings.
The 3057NA is a T25 wedge-style bulb, meaning it uses a wedge base rather than a bayonet mount. This base type differs from the BAY15d bayonet base found on the 2357NA and 2057NA, making cross-substitution between wedge and bayonet types physically incompatible without modification.
The 2057NA shares the same BAY15d bayonet base and 12V, 26.9W/8W ratings as the 2357NA. Both carry natural amber glass. The 2057NA is noted as a brighter variant of the 1157 bulb, a distinction that applies equally to its non-amber counterpart, the 2057.
The rear turn signal on the R/V Series transitioned from the 2057 to the 3057 between the 1988 and 1990 model years. The 2057 was fitted for 1987-1989, while the 3057 replaced it for 1990-1991.
The 3057 and 3057NA share identical electrical specifications at 12V and 27W/7W, differing only in that the 3057NA incorporates natural amber glass. Both use the T25 wedge base format.
The 2057 and 2057NA are similarly matched in voltage and wattage at 12V and 26.9W/8W, with the NA suffix indicating the addition of natural amber-tinted glass. Both use the BAY15d bayonet base.
Natural amber glass, indicated by the NA suffix on several of these bulbs, produces an amber-colored output without the use of an external lens filter. This allows the bulb itself to meet amber turn signal requirements independent of the housing color.
All five bulb types listed across these specifications conform to ANSI standards applicable in both the United States and Canada, placing them within a standardized classification system that governs base type, filament wattage, and voltage ratings.
The dual-filament construction present in all listed bulbs serves two separate circuit functions within a single housing, typically allowing one filament to operate as a running or parking light and the other as the turn signal or brake light.