The GMC V2500 Suburban front turn signal uses 3057NA or 2057NA bulb sizes, while the rear turn signal requires a 2057 bulb size. The replacement chart covers 1987 through 1991 model 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 GMC V2500 Suburban uses three distinct bulb types across its front and rear turn signal positions: the 3057NA, 2057NA, and 2057.
The 3057NA is a dual-filament wedge bulb in a T25 form factor, rated at 12V with a 27W high filament and 7W low filament, and features natural amber glass that produces an amber color output without the need for an amber lens.
The 2057NA and 2057 share the same BAY15d bayonet base and identical electrical ratings of 12V, 26.9W high filament and 8W low filament, making them functionally interchangeable in terms of power draw and base fitment.
The sole distinction between the 2057NA and the 2057 is the glass coating: the 2057NA has natural amber glass, while the 2057 uses clear glass. This difference affects the color of light emitted and is relevant when the housing lens does not provide amber filtering on its own.
Both the 2057NA and 2057 are described as brighter variants of the 1157, meaning they produce more light output despite sharing the same BAY15d base and similar wattage profile as the 1157.
All three bulb types conform to ANSI standards recognized in both the United States and Canada, indicating standardized performance and dimensional specifications across North American markets.
The front turn signal position on the GMC V2500 Suburban shifted from the 2057NA to the 3057NA between the 1988 and 1989 model years, representing a change in both bulb form factor and base type.
The rear turn signal position uses the 2057 across all model years from 1987-1991, while the front position uses two different bulb types across that same span, meaning front and rear turn signal bulbs are not interchangeable for the 1989-1991 model years.
The dual-filament design present in all three bulb types allows a single bulb to serve both a lower-intensity running or parking function and a higher-intensity signaling function within the same housing.
The 3057NA wedge base and the 2057NA bayonet base are physically incompatible with each other, so the socket type in the vehicle housing determines which bulb type is applicable for a given model year and position.