Mercedes-Benz S350 License Plate Bulb Size

The Mercedes-Benz S350 license plate light uses 12961 and DE3423 bulb sizes according to the provided specifications for the lighting system. Data for the specific bulb sizes covers the range from 1994 through 2013.

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
2012-2013	12961	Check Price
2006	DE3423	Check Price
1994-1995	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

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Additional Notes

The Mercedes-Benz S350 license plate bulbs fall into two distinct types across its model years: the 12961, a miniature wedge bulb, and the DE3423, a festoon bulb. These two types are not interchangeable due to their fundamentally different base designs.
The 12961 is a Philips part number designation for a T10 wedge bulb with a W2.1x9.5d base. This base type uses a plastic wedge with embedded wire contacts rather than a separate metal cap, which is what distinguishes it from festoon designs.
The 12961 operates at 12V and 5W. The T10 designation refers to the bulb's tubular form factor, which is among the most widely used sizes in automotive interior and exterior lighting applications.
The DE3423 is an ANSI-standardized festoon bulb recognized across the United States and Canada. Festoon bulbs make electrical contact through metal end caps at both tips rather than through a base socket, which is a defining characteristic of the festoon format.
The DE3423 has a 41mm length and operates at 12V. The 41mm specification refers to the distance between the two end contacts, which determines physical fitment within the lamp housing.
The 2012-2013 S350 uses the 12961 wedge bulb, while the 1994-1995 and 2006 model years use the DE3423 festoon bulb. A vehicle owner sourcing a replacement should confirm the exact model year before selecting a bulb, as the two types require different socket configurations.
The DE3423 carries no wattage figure in the provided specifications, whereas the 12961 is rated at 5W. Both bulbs share the same 12V operating voltage, which is standard for automotive electrical systems.