The Lincoln MKS front turn signal uses 3457NA or 3357NA bulb sizes, while the rear turn signal requires a 12271NA bulb size. The replacement chart covers 2009 through 2012 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lincoln MKS front turn signal uses the 3457NA bulb for the 2010-2012 model years, while the 2009 model year uses the 3357NA bulb instead.
The 3457NA is a dual-filament T25 wedge bulb rated at 12V with a 27W main filament and a 7W secondary filament, conforming to ANSI standards recognized in both the United States and Canada.
The 3357NA is a single-filament T25 wedge bulb rated at 12V and 27W, also conforming to the same ANSI standard as the 3457NA.
Although the 3457NA and 3357NA share the same T25 wedge form factor and natural amber glass, they are not interchangeable due to the filament count difference. The 3457NA carries two filaments while the 3357NA carries one.
Natural amber glass, denoted by the "NA" suffix on both front turn signal bulbs, produces an amber color through the glass itself rather than through a coating or lens tint.
The rear turn signal on the Lincoln MKS uses the 12271NA across all four model years, spanning 2009-2012, making it the only turn signal position with no year-to-year variation in bulb size.
The 12271NA is identified by an OEM part number rather than an ANSI standard designation, which distinguishes it from the front turn signal bulbs in terms of classification.
The 12271NA is also a natural amber glass variant rated at 12V, sharing those two characteristics with the front turn signal bulbs despite its different part number classification.