GMC Sonoma front turn signal bulbs use 3157, 3157NA, or 2057 sizes, while rear turn signal bulbs use 3057 or 2057 sizes. The replacement chart covers 1991 to 2004 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 Sonoma front turn signal uses three distinct bulb sizes across its 1991-2004 production span: the 2057 for 1991-1994, the 3157NA for 1995-2001, and the 3157 for 2002-2004.
The 3157NA is a natural amber glass variant of the standard 3157. Both share the same T25 wedge base and identical 12V, 27W/7W dual-filament ratings, meaning the amber tint is built into the glass rather than achieved through a clear bulb and colored lens.
The 3157 and 3057 are both T25 wedge bulbs rated at 12V, 27W/7W, yet they are not the same part. Their internal filament configurations differ, which affects circuit compatibility, and substituting one for the other is not supported by these specifications.
The 2057 uses a BAY15d bayonet base, which is physically incompatible with the T25 wedge socket used by the 3157, 3157NA, and 3057. A socket adapter would be required for any cross-substitution, and none is indicated in these specifications.
The 2057 is rated at 12V, 26.9W/8W and is described as a brighter variant of the 1157. Its high-filament wattage of 26.9W is marginally lower than the 27W high filament of the 3157-series bulbs.
The GMC Sonoma rear turn signal transitioned from the 2057 (1991-1993) to the 3057 (1994-2004), representing a base-type change from BAY15d bayonet to T25 wedge at the 1994 model year.
For the 1991-1993 model years, both the front and rear turn signals share the same 2057 bulb, while from 1994 onward the front and rear positions require different bulb types.
All four bulb types listed are dual-filament designs, meaning each bulb serves two lighting functions, typically combining the turn signal function with either a parking light or brake light function within a single housing.
All bulbs in these specifications conform to ANSI standards applicable in both the United States and Canada, indicating standardized photometric and dimensional requirements across that market region.
The 3057 is used exclusively in the rear turn signal position across 1994-2004, while the front position for those same years calls for either the 3157NA or 3157, confirming that front and rear sockets are not interchangeable despite all three sharing the T25 wedge form factor.