Mercury Milan front turn signal bulbs use 3357NA or 3457NA sizes, while rear turn signal bulbs use 3157NA size. The replacement chart covers 2006 through 2011 production 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 Mercury Milan uses three bulb types across its front and rear turn signal positions: the 3357NA, 3457NA, and 3157NA, all of which conform to ANSI standards recognized in the United States and Canada.
All three bulb types share the T25 wedge form factor and operate on a 12-volt electrical system, which reflects the standard low-voltage architecture common to passenger vehicles of this era.
The 3457NA and 3157NA are dual-filament bulbs rated at 27W and 7W, meaning each bulb serves two brightness levels within a single housing, typically supporting both turn signal and parking light functions simultaneously.
The 3357NA, used in the front turn signal position for the 2010-2011 Mercury Milan, is a single-filament bulb rated at 27W, which means it supports only one brightness level rather than the dual-function capability of the other two types.
The front turn signal position on the Mercury Milan uses the 3457NA for model years 2006-2009 and transitions to the 3357NA for 2010-2011, representing a shift from a dual-filament to a single-filament application in that position.
The 3457NA and 3357NA share the same T25 wedge base and 27W high-filament rating, but they are not directly interchangeable due to the difference in filament count, as substituting a single-filament bulb where a dual-filament is specified would disable one of the intended lighting functions.
The rear turn signal position on the Mercury Milan uses the 3157NA consistently across all model years from 2006-2011, making it the only bulb type in these specifications with no year-to-year variation in its assigned position.
The 3157NA and 3457NA are both dual-filament T25 wedge bulbs with identical wattage ratings of 27W/7W, though they carry different ANSI part numbers and are not confirmed as interchangeable by these specifications.
The "NA" suffix on all three bulb types denotes natural amber glass, which produces an amber-colored output without the use of an external amber lens, satisfying turn signal color requirements through the bulb itself.