Lincoln MKT Dome Light Bulb Size

The Lincoln MKT dome light utilizes bulb sizes 12961 and 578 for interior illumination across various production versions. Data for the specified lighting components covers the period from 2010 through 2019.

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
2013-2019	12961
2011-2012	578
2010	12961

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, 12W.	578

Other Locations

Additional Notes

The Lincoln MKT dome light draws from two distinct bulb types across its production run: the 12961 miniature wedge and the 578 festoon.
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 578 is an ANSI-standardized festoon bulb used in the US and Canadian markets, measuring 41mm in length with end-cap contacts, rated at 12V and 12W.
The W2.1x9.5d base on the 12961 is a wedge-type fitting where the bulb's glass pinch serves as the base, seating directly into a corresponding socket without a separate metal shell.
The 578's end-cap contact design means electrical contact is made at both ends of the bulb's cylindrical body, which is characteristic of festoon-style fitment.
At 12W, the 578 festoon draws more than twice the wattage of the 12961's 5W rating, making the two bulbs electrically incompatible as substitutes for one another despite both operating at 12V.
The Lincoln MKT (2013-2019) uses the 12961 wedge bulb for the dome light across all six model years in that span.
The 2011-2012 model years use the 578 festoon bulb, which is physically and electrically distinct from the 12961 used in surrounding years.
The 2010 Lincoln MKT uses the 12961 wedge bulb, placing it in the same specification as the 2013-2019 range despite the intervening 2011-2012 festoon years.
The difference in base type between the T10 wedge and the 41mm festoon means the two bulbs occupy non-interchangeable socket formats, and substitution between them is not physically possible without socket modification.