The Mercedes-Benz E500 front side marker bulb uses a 12961 size with P21/5W specification, while the rear side marker bulb requires a 12821 or 5008 size. The replacement chart covers 1994 to 2006 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 position on the Mercedes-Benz E500 uses the 12961 bulb across the 2003-2006 model years. This is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
The T10 wedge base format, identified by the W2.1x9.5d designation, is a push-in connector type that requires no rotation during installation. Both the 12961 and 12821 share this base configuration.
The 12821 is also a Philips-designated T10 miniature wedge bulb with a W2.1x9.5d base at 12V and 5W, used in the rear side marker position for the 2003 E500. Despite carrying a different part number than the 12961, both bulbs share identical base type, voltage, and wattage ratings.
The 1994 E500 front side marker uses the P21/5W bulb, an ECE-standard dual-filament signalling bulb with a BAY15d bayonet base rated at 12V with filaments at 21W and 5W. The BAY15d base features offset pins to prevent incorrect orientation during fitment.
The P21/5W bulb used in the 1994 front side marker position operates at a significantly higher wattage than the 12961 used in later model years. These two bulb types are not interchangeable due to differing base designs and wattage ratings.
The 1994 E500 rear side marker uses the 5008, an ANSI-standard single-filament bulb with a BA15s bayonet base rated at 12V. It is described as a lower wattage variant of the 1156 bulb family.
The BA15s base on the 5008 and the BAY15d base on the P21/5W are both bayonet-style connectors but are not interchangeable. The BAY15d base has offset pins to accommodate dual-filament alignment, while the BA15s uses symmetrical pins for single-filament applications.
The 1994 model year uses three distinct bulb types across its front and rear side marker positions, specifically the P21/5W and the 5008, reflecting different base standards and filament configurations between positions.
The 12961 and 12821 are both governed by Philips part numbering conventions rather than a universal ANSI or ECE standard designation, which distinguishes them from the P21/5W and 5008 entries in these specifications.
The rear side marker position for the 2003 E500 specifies the 12821, while the front side marker for the same year specifies the 12961. Although both are T10 wedge bulbs with identical electrical ratings, the two positions carry separate part number designations and are listed distinctly in the specifications.