The Ford F-350 Super Duty side marker uses a 194 bulb size for the lighting component. Data for the specific bulb application covers the range from 1999 to 2004.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ford F-350 Super Duty uses two bulb types across its side marker positions: the 194 and the 3157, both of which are ANSI-standardized bulbs for the US and Canadian markets.
The 194 is a T10 miniature wedge bulb rated at 12V and 3.78W, placing it in the low-wattage category suited for small indicator and marker applications.
The 3157 is a T25 dual-filament wedge bulb rated at 12V with a 27W/7W output, meaning it carries separate filaments for two distinct brightness levels within a single housing.
The front side marker position uses the 194 bulb across all model years covered in the specifications, from 1999 through 2023.
The rear side marker position is not uniform across the same span of years, with the 3157 and 194 appearing in different years depending on the model year.
The Ford F-350 Super Duty rear side marker uses the 194 bulb for the 2007-2010 model years, while surrounding model years use the 3157, making direct substitution between those groups incorrect.
For the 2017-2020 model years, both the front and rear side marker specifications carry a "With Halogen Capsule Headlamps" condition, indicating the listed bulb sizes apply specifically to that headlamp configuration.
The 194 and 3157 use different wedge base sizes, T10 and T25 respectively, which means they are physically non-interchangeable despite both being wedge-type bulbs.
The wattage difference between the 194 at 3.78W and the 3157 at up to 27W reflects a significant gap in power draw, which is relevant to socket and circuit compatibility.
The dual-filament nature of the 3157 distinguishes it functionally from the single-filament 194, as the 3157 is capable of serving combined marker and signal functions through its two separate filaments.