The Mercedes-Benz S350 front side marker bulb utilizes 12961, 2357NA, or 1157 size specifications, while the rear side marker bulb requires P21/4W size. The replacement chart covers 1994 to 2013 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 front side marker on the Mercedes-Benz S350 uses the 12961 bulb for the 2012-2013 model years, as well as the 2006 model year. This is a Philips part number designating a miniature wedge-type T10 bulb with a W2.1x9.5d base, rated at 12V and 5W.
The T10 wedge base (W2.1x9.5d) on the 12961 bulb is a pin-free design that seats by friction within the socket, which is a common fitment method for low-wattage marker and courtesy lighting applications.
The 1995 Mercedes-Benz S350 front side marker uses the 2357NA bulb, an ANSI-standard dual-filament type with a BAY15d bayonet base, rated at 12V with filaments drawing 26.9W and 8W respectively. The "NA" suffix denotes natural amber glass, meaning the bulb produces amber light without relying on a colored lens.
The 1994 S350 front side marker uses the 1157, also an ANSI-standard dual-filament bulb with a BAY15d bayonet base, rated at 12V with filaments drawing 21W and 5W. It shares the same base type as the 2357NA but carries different wattage ratings across both filaments.
Although the 1157 and 2357NA share the BAY15d bayonet base, they are not interchangeable without consequence. The wattage difference between the two, particularly on the high filament (21W versus 26.9W), affects light output and may affect compliance with marker lighting standards.
The rear side marker on the Mercedes-Benz S350 uses the P21/4W bulb across the 1994, 1995, and 2006 model years. This is an ECE-standard dual-filament signalling bulb rated at 12V with filaments drawing 21W and 4W.
The P21/4W uses a BAZ15d bayonet base, which offsets the two base pins at different heights. This asymmetric pin placement is a deliberate anti-misfit feature that prevents the bulb from being inserted in the wrong orientation.
The BAY15d base used by the 1157 and 2357NA also features offset pins, but the pin offset geometry differs from the BAZ15d used by the P21/4W. These two base types are physically incompatible with each other despite both being dual-filament bayonet designs.
The P21/4W is governed by ECE regulations, which are the prevailing standards in Europe and many international markets, while the 1157 and 2357NA follow ANSI standards applicable in the United States and Canada. This distinction reflects regional regulatory differences in automotive lighting.
The front and rear side markers on the S350 use different bulb families across the listed model years, with the front position transitioning from dual-filament ANSI types in 1994-1995 to a single-filament T10 wedge type by 2006, while the rear position retains the P21/4W across all listed years.