Ford F-650 front and rear side marker bulbs utilize 12961 or 194 size bulbs at the front and 3157 or 194 size bulbs at the rear, with each bulb size corresponding to specific vehicle configurations. The replacement chart covers 2000 through 2022 model years with corresponding bulb size specifications for side marker applications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ford F-650 uses three distinct bulb types across its front and rear side marker positions: the 12961, the 194, and the 3157.
The 12961 is a Philips part number designation for 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 recognized in both the US and Canada, rated at 12V and 3.78W, making it slightly lower in wattage than the 12961.
The 3157 is an ANSI-standard T25 dual-filament wedge bulb rated at 12V with a 27W/7W output, where the two wattage values correspond to its high- and low-intensity filaments respectively.
The Ford F-650 front side marker uses the 12961 bulb for model years 2017-2019 and 2021-2022, while the 194 bulb applies to model years 2000-2003.
The rear side marker on the F-650 uses the 3157 for model years 2017-2019 and 2021-2022, and the 194 for model years 2000-2003.
The 12961 and 194 share the same T10 wedge form factor, though they carry different wattage ratings and different designation systems, one being a manufacturer part number and the other an ANSI standard.
Despite the physical similarity between the 12961 and 194, substituting one for the other without confirming voltage and wattage compatibility with the specific vehicle circuit is not advisable, as the two bulbs are listed under separate model year groups in the specifications.
The 3157 is a T25 bulb, which is a physically larger wedge format than the T10 used in the front side marker positions, meaning the rear and front side marker sockets on 2017-2019 and 2021-2022 F-650 models are not interchangeable.
The dual-filament nature of the 3157 rear side marker bulb indicates the rear side marker housing on 2017-2019 and 2021-2022 F-650 models is wired to support two separate brightness levels within a single bulb.