The Mercury Milan brake light utilizes a 3157NA bulb size for illumination across all listed vehicle configurations. Data for the specified component covers the period from 2006 through 2011.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercury Milan uses two distinct bulb types across its brake lighting system: the 3157NA for the standard brake lights and the 921 for the center high mount stop light, with both fitments remaining consistent across the 2006-2011 model years.
The 3157NA is a dual-filament bulb, meaning it serves two independent lighting functions within a single housing. In the context of brake lights, this design typically allows one filament to handle running light duty while the other handles the brighter stop light function.
The 3157NA carries a natural amber glass envelope, which is a defining characteristic of the "NA" suffix in the ANSI designation. This amber tint is built into the glass itself rather than applied as a coating.
The 3157NA operates at 12 volts with a wattage rating of 27W on the high-filament circuit and 7W on the low-filament circuit, reflecting its dual-filament construction.
The 921 is a single-filament wedge bulb rated at 12V and 16W, a lower wattage than the 3157NA high filament, consistent with its role in the center high mount stop light rather than the primary brake light position.
Both the 3157NA and 921 follow ANSI standards recognized in the United States and Canada, indicating standardized base and electrical specifications across those markets.
The 3157NA belongs to the T25 wedge form factor. The 921 belongs to the T15 wedge form factor. These two form factors are not interchangeable, as the physical base sizes differ.
The natural amber glass of the 3157NA distinguishes it from the clear-glass 3157, which shares the same electrical and base specifications. Substituting a clear 3157 in a position designed for the 3157NA would alter the light color output at that position.