Mercury Milan Dome Light Bulb Size

The Mercury Milan dome light requires a 578 bulb size for proper installation within the interior lighting housing. Available data for the specified vehicle covers the range from 2006 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
2006-2011	578

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V, 12W.	578

Other Locations

Additional Notes

The 578 bulb is the sole dome light bulb size listed for the Mercury Milan across all six model years covered in the specifications, spanning 2006-2011.
The 578 is a festoon-type bulb, meaning it is cylindrical in shape with flat metal contacts at each end rather than a screw or bayonet base.
Festoon bulbs are held in place by spring-loaded clips within the fixture, with the end-cap contacts completing the circuit at both terminals.
The 578 bulb has a length of 41mm, which is a critical fitment factor, as festoon bulbs of differing lengths will not seat correctly in the fixture even if the voltage and wattage ratings match.
The bulb operates at 12 volts and 12 watts, values consistent with standard automotive interior lighting powered directly from a vehicle's 12V electrical system.
The 578 designation follows ANSI standards recognized in both the United States and Canada, indicating a standardized specification rather than a proprietary part number.
Because festoon bulbs are defined by their physical length and contact style, substitutions require matching the 41mm length to maintain proper fitment in the Mercury Milan dome light socket.