Mercedes-Benz CL600 License Plate Bulb Size

The Mercedes-Benz CL600 license plate light uses 12961 and DE3423 bulb sizes for the exterior illumination system. Available data for the specified vehicle covers the range from 1998 through 2014.

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 Size
2007-2014	12961
2001-2006	DE3423
1998-1999	DE3423

Bulb Specifications

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

Other Locations

Additional Notes

The Mercedes-Benz CL600 uses two distinct license plate bulb types across its production span, with the DE3423 festoon bulb fitted to the 1998-1999 and 2001-2006 model years, and the 12961 miniature wedge bulb fitted to the 2007-2014 model years.
The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
The W2.1x9.5d base is a wedge-type connection in which the glass envelope itself acts as the retention mechanism, with no separate metal base or pins involved.
The DE3423 is an ANSI-standardized festoon bulb recognized across the United States and Canada, measuring 41mm in length and making electrical contact through metal end caps at each tip rather than a wedge or pin base.
Because the 12961 and DE3423 use fundamentally different base types, a wedge socket and a festoon socket are not interchangeable, and the bulb type must correspond to the socket design present in the vehicle for the specific model year.
The DE3423 specification does not include a wattage rating in the provided data, whereas the 12961 is explicitly rated at 5W, a common output level for license plate illumination applications.
Both bulb types operate on a 12V electrical system, which is standard for passenger vehicle lighting circuits.
The 41mm length of the DE3423 is a critical fitment factor, as festoon bulbs are sized by their overall length, and substituting a festoon bulb of a different length would result in poor contact or failure to seat within the housing.
The T10 designation of the 12961 refers to the bulb's tubular envelope width, expressed in eighths of an inch, placing it among the smaller wedge bulb formats used in automotive auxiliary lighting positions.
The transition from the DE3423 to the 12961 between the 2006 and 2007 CL600 model years reflects a change in socket design, meaning components from these two generations of the vehicle are not cross-compatible for this position.