Ford Bronco Turn Signal Bulb Size

Ford Bronco front turn signal bulbs utilize 3157, 1157, or 198 sizes, while rear turn signal bulbs use WT21/7W, 3157, or 1157 sizes depending on model generation. The replacement chart covers bulb specifications across 58 years of Bronco production from 1966 through 2023.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Front Turn Signal

Years	Bulb Size
1988-1996	3157
1979-1987	1157
1966-1978	198

Rear Turn Signal

Years	Bulb Size
2021-2023	WT21/7W
1988-1996	3157
1979-1987	1157
1966-1978	198

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3157
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V, 21W/5W.	1157
ANSI standard (US & Canada). Miniature wedge bulb (T5). 12V, 2W.	198
Ford OEM part. Dual-filament wedge bulb (T20). Originally used in 2021+ Ford F-150, Bronco, and Maverick. 12V, 21W/7W.	WT21/7W

Other Locations

Additional Notes

The Ford Bronco front turn signal specifications cover model years 1966-1996, while the rear turn signal specifications extend further to include 2021-2023, reflecting the nameplate's reintroduction after a long production gap.
Three distinct bulb types appear across the front turn signal positions of the Ford Bronco: the 198 for 1966-1978, the 1157 for 1979-1987, and the 3157 for 1988-1996.
The 3157 is a dual-filament T25 wedge bulb rated at 12V with a 27W high-filament and 7W low-filament output, conforming to ANSI standards applicable in both the United States and Canada. Its dual-filament design allows a single bulb to serve both turn signal and parking light functions simultaneously.
The 1157 uses a BAY15d bayonet base rather than a wedge-style fitting, which makes it physically incompatible with sockets designed for the 3157 despite both being dual-filament 12V bulbs. The 1157 is rated at 21W/5W, giving it a lower output than the 3157 on both filaments.
Although the 3157 and 1157 share the same dual-filament function and voltage rating, their base types differ entirely. The 3157 uses a wedge base while the 1157 uses a bayonet base, meaning the two are not interchangeable without a socket adapter.
The 198 is a single-filament miniature T5 wedge bulb rated at 12V and only 2W, placing it in a significantly lower power class than either the 1157 or 3157. Its low wattage reflects its role as a small indicator lamp rather than a combined signal and parking light source.
The WT21/7W is a Ford OEM part rather than an ANSI-standardized bulb. It is a dual-filament T20 wedge bulb rated at 12V, 21W/7W, and was originally introduced on the 2021 Ford F-150, Bronco, and Maverick.
The rear turn signal of the 2021-2023 Ford Bronco uses the WT21/7W, which shares its T20 wedge form factor with the widely available W21/7W type but carries Ford OEM designation, indicating that fitment should be confirmed against OEM part numbers rather than assumed from form factor alone.
For the 1988-1996 Ford Bronco, both the front and rear turn signal positions share the same 3157 specification, meaning a single bulb type covers all four turn signal sockets on those model years.
The same front-to-rear bulb consistency applies to the 1979-1987 model years with the 1157, and to the 1966-1978 model years with the 198, in each case allowing a single bulb type to serve both front and rear turn signal positions across those respective production spans.