The Mercedes-Benz GL320 parking light requires a bulb size of 12961 for the lighting system. Data for the specified component covers the range from 2007 to 2009.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 12961 is a Philips part number designating a miniature wedge bulb in the T10 form factor with a W2.1x9.5d base, rated at 12 volts and 5 watts.
The T10 designation refers to the bulb's tubular shape, while the W2.1x9.5d base describes a wedge-type connection where the electrical contacts are made through the glass pinch at the base rather than through metal pins or a bayonet fitting.
At 5 watts, the 12961 is a low-power bulb, consistent with its role as a parking light rather than a primary illumination source.
The Mercedes-Benz GL320 uses the 12961 bulb for the front parking light across the 2007-2009 model years.
The W2.1x9.5d wedge base is a standardized fitting, meaning functionally equivalent bulbs from other manufacturers sharing the same base type and electrical rating are generally interchangeable with the Philips 12961.