The Mercedes-Benz S600 front side marker bulb utilizes 12961 or 2357NA size specifications, while the rear side marker bulb employs P21/4W, 12821, or P21/5W size options. The replacement chart covers 1994 through 2013 production years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz S600 front side marker position uses the 12961 bulb across the 2001-2013 model years, making it the most consistently specified bulb in these listings. It is a Philips-numbered miniature wedge type in the T10 form factor, rated at 12V and 5W, with a W2.1x9.5d base.
The 12821 shares the same T10 wedge form factor, W2.1x9.5d base, 12V rating, and 5W output as the 12961. Both are Philips part numbers designating physically and electrically equivalent miniature wedge bulbs, with the 12821 specified for the rear side marker on the 2001-2002 S600.
The front side marker on the 1995-1999 S600 uses the 2357NA, an ANSI-standard dual-filament bulb with a BAY15d bayonet base rated at 12V with a 26.9W high filament and an 8W low filament. The natural amber glass coating is built into the bulb itself rather than the lens.
The BAY15d base on the 2357NA features two offset pins at different heights, which mechanically prevents incorrect filament orientation during installation. This base type is not interchangeable with the BAZ15d base used on the P21/4W.
The rear side marker on the 1995 S600 and the 2003-2006 S600 both specify the P21/4W, an ECE-standard dual-filament bulb rated at 12V with a 21W and 4W filament combination. It uses a BAZ15d bayonet base, which has two pins at the same height but offset radially to enforce a single insertion orientation.
The P21/5W, specified for the rear side marker on the 1996-1999 S600, also uses a BAY15d base, the same base type as the 2357NA. However, the two bulbs are not interchangeable due to differences in wattage, filament configuration, and regulatory standard.
The P21/4W and P21/5W share the same 21W primary filament rating but differ in their secondary filament output, at 4W and 5W respectively. Despite this similarity, their different base types, BAZ15d versus BAY15d, physically prevent cross-substitution.
The rear side marker position on the S600 uses four distinct bulb types across its model range, reflecting a higher degree of variation in that position compared to the front, where the T10 wedge format dominates the majority of listed years.
The 2357NA is the only bulb in these specifications classified under the ANSI standard applicable to the US and Canadian markets. All P-designated bulbs follow the ECE standard used in European and worldwide regulatory contexts.
The W2.1x9.5d base designation on both the 12961 and 12821 refers to a wedge-type connection where the bulb glass itself acts as the retention mechanism, with no separate metal base pins. This base type is standard across T10 miniature wedge bulbs.