The Mercedes-Benz Sprinter front turn signal requires a 3457NA bulb size, while rear turn signal applications use either PY21W or P21W bulb sizes. The replacement chart covers vehicle production spanning 2010 to 2025 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 3457NA bulb is the front turn signal size for the Mercedes-Benz Sprinter across all listed model years from 2010-2025, making it the most consistently specified bulb in these fitment records.
The 3457NA is a dual-filament wedge bulb built to the ANSI standard used in the United States and Canada. It operates at 12V with a 27W primary filament and a 7W secondary filament, and its T25 body is made with natural amber glass rather than a clear envelope with a colored coating.
Because the 3457NA uses natural amber glass, it produces amber light directly from the bulb itself. This is a relevant distinction when considering replacement options, as clear-glass equivalents would not meet the same amber output requirement.
The PY21W is the rear turn signal size for the Sprinter across all listed model years from 2010-2025. It is a single-filament bulb rated at 12V and 21W, built to the ECE standard used in Europe and internationally.
The PY21W uses a BAU15s bayonet base, which is an offset-pin base. This base is not interchangeable with the BA15s base found on the P21W, even though both bulbs share the same 12V, 21W rating. Substituting one for the other is not physically compatible without modification.
For the 2019 Sprinter, the rear turn signal position lists two separate bulb sizes: a PY21W on the tail lamp and a P21W for an auxiliary function. These are distinct sockets requiring different bulbs despite their similar specifications.
The P21W uses a BA15s bayonet base with symmetrically placed pins, while the PY21W uses a BAU15s base with one pin offset by 150 degrees. The physical difference in base design prevents cross-installation between the two types.
The front turn signal fitment for 2019-2022 Sprinter models carries a notation specifying halogen headlamps. This indicates the 3457NA size applies specifically to that headlamp configuration for those years.
The 3457NA and PY21W serve different regulatory markets. The 3457NA conforms to ANSI standards applicable in North America, while the PY21W conforms to ECE regulations. The Sprinter specifications reflect both standards across its front and rear positions respectively.
The 3457NA's dual-filament design contrasts with the single-filament construction of both the PY21W and P21W. A dual-filament bulb can serve two separate lighting functions from one unit, while a single-filament bulb is dedicated to one function per socket.