Mercedes-Benz S550 Map Light Bulb Size

The Mercedes-Benz S550 map light utilizes bulb sizes 12961 and H6W according to the provided specifications for the interior lighting components. Available data covers the range from 2007 through 2013 for the specified vehicle and component.

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
2009-2013	12961
2007-2008	H6W

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961
ECE standard (Europe & worldwide). Single-filament signalling bulb with BAX9s base. 12V, 6W.	H6W

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Additional Notes

The Mercedes-Benz S550 map light specifications cover model years 2007-2013, with two distinct bulb types used across that span.
The 12961 is a Philips part number designation for a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
The H6W follows ECE (Economic Commission for Europe) standards, making it a globally recognized specification. It is a single-filament signalling bulb with a BAX9s base, rated at 12V and 6W.
The BAX9s base of the H6W and the W2.1x9.5d wedge base of the 12961 are physically incompatible, meaning the two bulb types are not interchangeable.
The S550 uses the H6W for model years 2007-2008.
The S550 uses the 12961 for model years 2009-2013.
The H6W carries 1 additional watt of power compared to the 12961, though both operate on a 12V electrical system.
The T10 wedge form factor of the 12961 is among the most widely used miniature bulb formats in automotive interior lighting applications.
The BAX9s base of the H6W features an offset pin arrangement, a design that prevents incorrect bulb insertion into the socket.
A 2007-2008 S550 socket is designed for the BAX9s base, and fitting a wedge-base 12961 into that socket without an adapter is not possible.