GMC Savana front side marker bulbs use 194 size while rear side marker bulbs use 3157 size. The replacement chart covers vehicle production from 1996 through 2024.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The GMC Savana uses the 194 bulb for the front side marker position across all listed model years from 1996-2024, making it the most consistently specified bulb in these fitment records.
The 194 is an ANSI-standard miniature wedge bulb rated at 12V and 3.78W, with a T10 wedge base that seats directly into a compatible socket without a separate holder or retaining clip.
The 3157 is an ANSI-standard dual-filament wedge bulb rated at 12V with a 27W high filament and a 7W low filament, housed in a T25 wedge body. Its dual-filament design allows a single bulb to serve both a brighter and a dimmer function within the same circuit.
The rear side marker position on the GMC Savana uses the 3157 bulb for the 2017-2018 and 2021-2024 model years.
The 194 and 3157 are both ANSI-standardized for the United States and Canada, meaning their physical and electrical specifications conform to a defined industry standard rather than a proprietary manufacturer format.
Although both the 194 and 3157 use wedge-style bases, they are not interchangeable. The T10 base of the 194 and the T25 base of the 3157 differ in physical size, and their wattage ratings are also substantially different, which would make cross-substitution electrically and physically incompatible.
The 3157's dual-filament construction distinguishes it from the single-filament 194. Installing a single-filament substitute in a socket wired for dual-filament operation would result in the loss of one functional circuit.
The 194 bulb's low 3.78W draw reflects its role as a low-intensity marker light rather than a signaling or braking light, consistent with its front side marker application on the Savana.