The Ford F-450 Super Duty front side marker uses a 12961 or 194 bulb size, while the rear side marker requires a 3157 or 12961 bulb size. The replacement chart covers vehicle production years spanning 1999 to 2022 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 Ford F-450 Super Duty front side marker position uses two distinct bulb sizes across its model year range. The 194 bulb was specified for the 1999-2010 model years, while the 12961 replaced it from 2011 onward through 2022.
The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W. The 194 is an ANSI-standard T10 miniature wedge bulb rated at 12V and 3.78W. Both share the T10 form factor, though their wattage and designation systems differ.
Because the 194 and 12961 are both T10 wedge bulbs, physical fitment between the two is closely related. However, substituting one for the other without confirming the correct specification for a given model year carries a risk of mismatched wattage output.
The rear side marker position on the Ford F-450 Super Duty uses the 3157 bulb for the 2011-2022 model years. For 2007-2010, the rear side marker instead used the 12961.
The 3157 is an ANSI-standard T25 dual-filament wedge bulb rated at 12V with a 27W/7W filament configuration. Its dual-filament design distinguishes it functionally from the single-filament T10 bulbs used in the front side marker position.
The T25 base of the 3157 is physically incompatible with the T10 socket used by the 12961 and 194. A bulb from the front side marker position cannot be used as a direct replacement in the rear side marker socket, and vice versa.
For the 2017-2019 model years, both the front and rear side marker specifications carry a "With Halogen Capsule Headlamps" qualifier. This indicates the listed bulb sizes apply specifically to F-450 Super Duty trucks equipped with that headlamp configuration during those years.
The 2021-2022 front side marker entries list the 12961 without any headlamp qualifier, as do the 2011-2016 entries. The same pattern applies to the rear side marker 3157 entries for those same years.
The 12961 appears in both the front and rear side marker positions across the full specification set, though not simultaneously for the same model year. It serves as the front marker bulb from 2011-2022 and as the rear marker bulb from 2007-2010.
The 194 bulb, used in the front side marker of the F-450 Super Duty for 1999-2010, operates at a lower wattage than the 12961 at 3.78W versus 5W. This difference is relevant when assessing socket load compatibility during any bulb substitution.