The Mercedes-Benz C55 AMG front turn signal uses 1156NA or 2357NA bulb sizes, while the rear turn signal requires 12496 or PY21W bulb sizes. The replacement chart covers 2005 to 2006 model 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 is a single-filament bulb rated at 12V and 21W, built to ANSI standards for the US and Canadian markets. It uses a BA15s bayonet base and features natural amber glass to produce the required amber turn signal color without relying on a colored lens.
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. It conforms to ANSI standards and uses a BAY15d bayonet base, which is a staggered-pin variant that prevents incorrect single-filament bulbs from being seated in its place.
The PY21W conforms to ECE regulations used in Europe and worldwide markets. It is a single-filament amber bulb rated at 12V and 21W, mounted on a BAU15s bayonet base. The BAU15s base uses an offset pin arrangement distinct from both the BA15s and BAY15d bases, making it physically incompatible with those sockets.
The 12496 is a Philips/Osram part number designation rather than an ANSI or ECE standard code. It is classified as a halogen bulb for a specialty application and is rated at 12V.
On the Mercedes-Benz C55 AMG, the front turn signal bulb size for 2005-2006 is determined by headlamp type. Vehicles fitted with halogen capsule headlamps use the 1156NA, while vehicles fitted with HID headlamps use the 2357NA instead.
The front turn signal socket type differs between headlamp configurations on the C55 AMG. The BA15s base of the 1156NA and the BAY15d base of the 2357NA are not interchangeable, so substituting one bulb for the other is not physically possible without a socket adapter.
The rear turn signal specification changed between model years on the C55 AMG. The 2005 model year uses the PY21W, while the 2006 model year uses the 12496.
Because the PY21W uses a BAU15s base and the 12496 is a specialty halogen type, the rear turn signal bulbs from the 2005 and 2006 model years are not directly interchangeable without confirming socket compatibility.