Ford Transit Brake Bulb Size

Ford Transit brake bulbs utilize a P21/5W size, also designated as 3057, for replacement applications across multiple model generations. The replacement chart covers vehicle production spanning 2015 to 2023 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.

Bulb Size by Year Range

Years	Bulb Size
2023	P21/5W
2015-2020	3057

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3057

Other Locations

Additional Notes

The Ford Transit uses two distinct brake bulb types across its model years: the P21/5W for the 2023 model year and the 3057 for the 2015-2020 model years.
The 3057 is an ANSI-standard bulb used in North American markets, while the P21/5W follows ECE standards common in Europe and other international markets.
Both bulb types are dual-filament designs, meaning a single bulb serves two brightness levels, typically one for running light function and one for the braking signal.
The 3057 operates at 12V with filament ratings of 27W and 7W, housed in a T25 wedge base form factor.
The P21/5W operates at 12V with filament ratings of 21W and 5W, and uses a BAY15d bayonet base rather than a wedge-style fitting.
The BAY15d bayonet base of the P21/5W and the T25 wedge base of the 3057 are physically incompatible, meaning the two bulb types are not interchangeable despite both being dual-filament 12V units.
The wattage difference between the two types is notable: the 3057 draws more power on both filaments (27W/7W) compared to the P21/5W (21W/5W), which reflects the differing output expectations between ANSI and ECE standards.