Mercedes-Benz C350 License Plate Bulb Size

The Mercedes-Benz C350 license plate light requires 12961 and DE3423 bulb sizes for the exterior lighting system. Data for the specified components covers the period from 2006 through 2011.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Type	Shop
2008-2011	12961	Check Price
2006-2007	DE3423	Check Price

Bulb Specifications

Description	Type	Shop
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961	Check Price
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V.	DE3423	Check Price

Other Locations

Additional Notes

The Mercedes-Benz C350 license plate position uses two distinct bulb types across its model years, with the 2008-2011 models specifying the 12961 and the 2006-2007 models specifying the DE3423.
The 12961 is a Philips part number designation for a T10 miniature wedge bulb. It operates at 12 volts and draws 5 watts, with a W2.1x9.5d wedge base that requires no retaining clips or holders beyond the socket itself.
The DE3423 is an ANSI-standardized festoon bulb measuring 41mm in length. Festoon bulbs make electrical contact through metal end caps at each tip rather than through a wedge or pin base, which makes the mounting style fundamentally different from the T10 wedge format.
The T10 wedge base of the 12961 and the end-cap contact design of the DE3423 are physically incompatible with each other. A bulb specified for 2006-2007 cannot be installed in a 2008-2011 socket, and vice versa.
The DE3423 festoon format is common across many vehicle makes and aftermarket lighting products, though fitment to a specific socket depends on the 41mm length matching the holder span in the Mercedes-Benz C350 (2006-2007) license plate assembly.
The 12961 carries a manufacturer-specific part number from Philips rather than a universal ANSI code, which means cross-referencing to equivalent T10 5W bulbs from other manufacturers requires verifying that the W2.1x9.5d base specification matches.
Both bulb types operate on a 12-volt electrical system, consistent with standard automotive low-voltage architecture, though the wattage of the DE3423 is not specified in the provided data.