The Mercedes-Benz R350 uses PY24WNA and 3457NA bulbs for front turn signals, while rear turn signals require 12496 and PY21W bulbs in these specific sizes. A replacement chart covering 2006 to 2012 model years documents the bulb specifications for this vehicle.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz R350 front turn signal uses two distinct bulb types across its model years: the 3457NA for 2006-2010 and the PY24WNA for 2011-2012.
The 3457NA is an ANSI-standard dual-filament bulb in a T25 wedge form with natural amber glass, rated at 12V and drawing 27W on its primary filament and 7W on its secondary filament.
The PY24WNA is an ANSI-standard single-filament bulb rated at 12V and 24W, fitted with a PGU20-4 base, and represents the North American amber variant of the ECE PY24W specification.
Because the 3457NA and PY24WNA differ in base type, filament count, and wattage, they are not interchangeable with each other despite both serving the front turn signal position on the R350.
The rear turn signal of the R350 does not follow a consistent single bulb type across its production run, with the 12496 and PY21W alternating across model years rather than transitioning at a single point.
The PY21W carries an ECE designation, meaning it was developed under European and international standards, while the ANSI-designated bulbs in the same specifications were developed under North American standards.
The PY21W uses a BAU15s bayonet base, which has an offset pin arrangement that prevents accidental installation of non-amber bulbs in amber-designated sockets.
The 12496 is a Philips/Osram proprietary part number rather than an ANSI or ECE designation, indicating it is a manufacturer-specific halogen bulb rated at 12V for a specialty application.
For the 2009 and 2010 rear turn signal positions, the R350 specifies different bulbs, the PY21W and 12496 respectively, making year-specific verification necessary before replacement.
The PY24WNA and PY21W share amber coloring and single-filament construction but differ in base type, wattage, and regulatory standard, making them incompatible substitutes for one another.