The Mercedes-Benz R500 front turn signal requires a 3457NA bulb size, while the rear turn signal uses either PY21W or 12496 bulb sizes. The replacement chart covers 2006 to 2007 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 3457NA is an ANSI-standard dual-filament bulb rated at 12V with a 27W main filament and a 7W secondary filament, housed in a T25 wedge form with natural amber glass. Its natural amber designation means the glass itself produces the amber color rather than relying on a painted or coated lens.
The Mercedes-Benz R500 front turn signal position uses the 3457NA for both 2006-2007 model years, making it consistent across that production span.
The dual-filament design of the 3457NA allows a single bulb to serve two lighting functions simultaneously, which is a common arrangement in North American vehicle lighting where turn signal and parking light circuits share one housing.
The rear turn signal position on the R500 does not share a consistent bulb type between 2006 and 2007, as each year specifies a different bulb entirely.
The 2007 R500 rear turn signal uses the PY21W, an ECE-standard single-filament bulb rated at 12V and 21W. It features a BAU15s bayonet base, which has offset pins that prevent accidental installation of an incompatible bulb into the same socket.
The BAU15s base on the PY21W is not interchangeable with the more common BA15s base. The offset pin configuration is a deliberate fitment control, meaning a standard single-filament bulb with a BA15s base cannot be substituted without a socket adapter.
The 2006 R500 rear turn signal uses the 12496, a Philips/Osram part number designating a specialty halogen bulb rated at 12V. Because 12496 is a manufacturer-specific designation rather than an ANSI or ECE standard number, cross-referencing to a generic equivalent requires consulting manufacturer compatibility data.
The PY21W carries an ECE rating, indicating it meets European and international lighting regulations, while the 3457NA carries an ANSI rating applicable to the United States and Canada. These two standards govern different photometric and safety requirements, and bulbs certified under one standard are not automatically compliant under the other.