Mercury Mariner License Plate Bulb Size

The Mercury Mariner license plate light requires 168 or 12961 bulb sizes depending on the specific version of the vehicle. Data for the bulb specifications covers the range from 2005 to 2011.

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
2007-2011	168
2005-2006	12961

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961

Other Locations

Additional Notes

The Mercury Mariner uses two distinct license plate bulb sizes across its model years, with the 168 fitted to the 2007-2011 models and the 12961 fitted to the 2005-2006 models.
Both the 168 and the 12961 are miniature wedge bulbs sharing the T10 form factor, meaning they occupy the same physical bulb category despite carrying different part designations.
The 168 is an ANSI-standardized bulb recognized across the US and Canadian markets, operating at 12 volts and rated at 4.9 watts.
The 12961 is a Philips-assigned part number rather than an ANSI industry code, operating at 12 volts and rated at 5 watts, with a W2.1x9.5d base specification.
The W2.1x9.5d base on the 12961 denotes a wedge-type base with a 2.1mm wire width and a 9.5mm pin spread, which is the standard base geometry for T10 wedge bulbs.
The wattage difference between the two bulbs is minimal, with the 168 rated at 4.9W and the 12961 at 5W, placing both within the same low-wattage class typical of license plate lighting applications.
Because both bulbs share the T10 wedge form factor and nearly identical voltage and wattage ratings, fitment overlap between the two designations is a relevant consideration when sourcing replacements for the Mercury Mariner (2005-2011).
The shift from the 12961 designation in 2005-2006 to the ANSI 168 designation in 2007 reflects a change in the specified part reference rather than a confirmed change in the underlying bulb construction.