Ford Five Hundred Dome Light Bulb Size

The Ford Five Hundred dome light requires a 578 bulb size for the interior lighting system. Data for the specified component covers the period from 2005 through 2007.

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
2005-2007	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 Ford Five Hundred (2005-2007) uses a 578 bulb for the dome light across all three model years.
The 578 is a festoon-style bulb, meaning it is cylindrical in shape and makes electrical contact through metal caps at each end rather than through a base socket.
At 41mm in length, the 578 fits into a spring-loaded festoon holder, where the end caps press against two opposing contact points inside the housing.
The 578 operates at 12 volts and 12 watts, which is a standard rating for interior dome lighting in passenger vehicles of this era.
The 578 carries ANSI designation, indicating it meets a standardized specification recognized in both the United States and Canada.
Because festoon bulbs are sized by length, a replacement must match the 41mm specification to seat correctly in the holder; a bulb of a different length will either fail to make contact or will not fit within the housing.