Mercedes-Benz GL550 License Plate Bulb Size

The Mercedes-Benz GL550 license plate light uses bulb size 12961 and bulb size DE3423 for the lighting system. Data for the lighting components covers the range from 2008 to 2012.

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
2012	12961
2008-2011	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 GL550 uses two distinct bulb types across its model years for the license plate position: the 12961 and the DE3423.
The DE3423 is an ANSI-standardized festoon bulb recognized across the US and Canadian markets. It measures 41mm in length and makes contact through end-cap terminals rather than a socket base, operating at 12 volts.
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 T10 wedge base of the 12961 and the end-cap festoon design of the DE3423 are physically incompatible with each other, meaning the two bulb types are not interchangeable despite both serving the license plate function.
The GL550 produced in 2008-2011 takes the DE3423 festoon bulb in the license plate position.
The 2012 GL550 uses the 12961 wedge bulb, which represents a different base type and wattage rating compared to the festoon unit used in prior years.
Because the 2012 model year requires a wedge-base bulb while earlier years require a festoon, a bulb sourced for a 2008-2011 GL550 would not fit the 2012 socket, and vice versa.
The DE3423 festoon format is a widely used standard in North American automotive applications, and compatible equivalents from various manufacturers are generally available under the same ANSI designation.