The Mercedes-Benz C230 front turn signal bulb uses 1156NA or 2357NA size, while the rear turn signal bulb uses PY21W, 12496, or P21W size. The replacement chart covers 1997 to 2007 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 1156NA and 2357NA bulbs follow ANSI standards used in the United States and Canada, while the PY21W and P21W bulbs follow ECE standards used in Europe and worldwide markets.
The 2357NA is a dual-filament bulb rated at 26.9W and 8W, operating on a BAY15d bayonet base. Its two filaments serve different brightness levels, which is typical for combined stop and turn signal functions.
The 1156NA is a single-filament bulb rated at 21W on a BA15s bayonet base. Its natural amber glass produces the amber signal color without relying on a colored lens.
The BA15s base of the 1156NA and the BAY15d base of the 2357NA are not interchangeable. The BAY15d base has offset pins to prevent incorrect installation of the dual-filament bulb in a single-filament socket.
For the Mercedes-Benz C230, the front turn signal bulb required depends on headlamp type. Models from 2003-2007 fitted with halogen capsule headlamps use the 1156NA, while those fitted with HID headlamps use the 2357NA.
The PY21W uses a BAU15s base, which has a different pin offset than both the BA15s and BAY15d bases, making it physically incompatible with sockets designed for ANSI-standard bulbs.
The P21W shares the BA15s base with the 1156NA and both are rated at 12V, 21W. However, the P21W has a clear glass envelope and relies on an amber lens for color, whereas the 1156NA has natural amber glass.
The 12496 is a Philips/Osram part number designation rather than an ANSI or ECE standard classification. It is a 12V halogen bulb intended for specialty automotive applications.
The rear turn signal on the 2007 C230 uses the PY21W, while the 1997 model uses the P21W. Both are ECE-standard single-filament bulbs rated at 12V, 21W, but they differ in base type and glass color.