Ford Bronco front side marker bulbs utilize 194NA, 3157, or 1157 bulb sizes, while rear side marker bulbs use WT21/7W or 3157 sizes depending on model generation. The replacement chart covers 1972 through 2023 production years with corresponding bulb size specifications for each generation.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 194 bulb is the most frequently specified front side marker bulb across the Ford Bronco's production history, covering model years 1972-1986 as well as 1992-1996 in its natural amber variant (194NA).
The 194NA is a T10 miniature wedge bulb rated at 12V and 3.78W. Its natural amber glass produces the amber color required for side marker lighting without relying on a tinted lens, distinguishing it from the standard 194, which uses a clear glass envelope.
The standard 194 and the 194NA share identical electrical ratings of 12V and 3.78W, as well as the same T10 wedge form factor. The sole difference between the two is the amber-tinted glass of the 194NA.
The Ford Bronco (1988-1991) used the 3157 for the front side marker position. The 3157 is a dual-filament T25 wedge bulb rated at 12V with a 27W high filament and a 7W low filament, making it significantly more powerful than the 194-series bulbs used in surrounding model years.
The 1987 Ford Bronco front side marker uses the 1157, a dual-filament bulb with a BAY15d bayonet base rated at 12V, 21W/5W. The bayonet base of the 1157 is physically incompatible with the wedge sockets used by the 3157 and 194-series bulbs, making direct substitution impossible without a socket adapter.
The rear side marker specification for the 2021-2023 Ford Bronco calls for the WT21/7W, a Ford OEM dual-filament T20 wedge bulb rated at 12V, 21W/7W. Its OEM designation indicates it was not part of a broad ANSI standard catalog at the time of its introduction.
The WT21/7W was originally introduced across the 2021 Ford F-150, Bronco, and Maverick, reflecting a shared platform-level component strategy across those vehicles.
The rear side marker for the 1994-1996 Ford Bronco uses the 3157, the same dual-filament T25 wedge bulb specified for the front side marker on the 1988-1991 models. Despite appearing in both positions, the front and rear applications on any single model year do not share the same bulb.
The 3157 rear side marker bulbs used on the 1994-1996 Bronco are not interchangeable with the 194NA front side marker bulbs used on those same years, as the two bulbs differ in base type, wattage, and filament configuration.
All bulb types listed across both the front and rear side marker positions operate on a 12V electrical system, consistent with standard automotive low-voltage architecture.