The Mercedes-Benz S320 front turn signal uses 2357NA and 1157 bulb sizes, while the rear turn signal requires PY21W, 1156NA, and P21W bulb sizes. The replacement chart covers 1994 to 1999 production years 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 2357NA is the most frequently specified bulb across these turn signal positions, appearing as the front turn signal fitment for the Mercedes-Benz S320 across the 1995-1999 model years.
The 2357NA is a dual-filament bulb rated at 12V with a high-filament draw of 26.9W and a low-filament draw of 8W, built to the ANSI standard used in the United States and Canada, and fitted with a BAY15d bayonet base.
The 1157 shares the same BAY15d bayonet base as the 2357NA but draws less power at 21W and 5W across its two filaments, making the two physically interchangeable at the socket level despite differing in wattage output.
The 2357NA and 1157 both carry natural or clear glass housings, while the 2357NA variant uses natural amber glass to produce its amber signal color without relying on a tinted lens.
The rear turn signal position on the S320 uses three distinct bulb types across the 1994-1999 model years, reflecting a mix of ANSI and ECE standards depending on the specific year.
The PY21W, specified for the 1998-1999 rear turn signal, follows the ECE standard common in European and worldwide markets and uses a BAU15s bayonet base, which is offset and not interchangeable with the BA15s base found on the 1156NA and P21W.
The 1156NA, specified for the 1994-1995 and 1997 rear turn signal, is a single-filament ANSI bulb with a BA15s base and natural amber glass, rated at 12V and 21W.
The P21W, specified for the 1996 rear turn signal, is also a single-filament ECE bulb with a BA15s base rated at 12V and 21W, making it dimensionally compatible with the 1156NA at the socket, though the two follow different regulatory standards.
The BAU15s base used by the PY21W has a pin offset of 150 degrees, whereas the BA15s base used by the 1156NA and P21W has pins set at 180 degrees, meaning these bulbs cannot be substituted for one another without a socket adapter.
The front turn signal position transitioned from the 1157 in 1994 to the 2357NA from 1995 onward, both of which share the BAY15d base, indicating the socket remained consistent while the bulb specification was updated.