Mercedes-Benz GL320 Map Light Bulb Size

The Mercedes-Benz GL320 map light requires a bulb size of 12961 for proper installation within the interior overhead lighting assembly. Data for the specified component covers the range from 2007 through 2009.

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
2007-2009	12961

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961

Other Locations

Additional Notes

The Mercedes-Benz GL320 uses the 12961 bulb for the map light across the 2007-2009 model years.
The 12961 is a Philips part number designating a miniature wedge bulb in the T10 form factor, operating at 12 volts and 5 watts.
The T10 designation refers to a tubular bulb with a nominal width of 10/8 of an inch, a standard sizing convention in miniature automotive lighting.
The W2.1x9.5d base type is a wedge-style connector, meaning the bulb is held in place by tension from the socket rather than by a bayonet or screw mechanism.
The "W2.1x9.5d" designation specifies the exact wedge base geometry, where 2.1 refers to the wire width in millimeters and 9.5 refers to the base length in millimeters, ensuring a precise socket fit.
At 5 watts, the 12961 is a low-output bulb suited for interior courtesy and reading applications rather than high-intensity exterior lighting functions.
Because the W2.1x9.5d base has defined physical tolerances, substituting a bulb with a different base type risks an improper fit even if the voltage and wattage ratings are otherwise compatible.