Ford Expedition Dome Light Bulb Size

The Ford Expedition dome light utilizes a 578 bulb size for interior illumination across various production versions of the vehicle. Available information covers a span from 1997 through 2018.

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
1997-2018	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 Expedition uses the 578 bulb size for the dome light across all listed model years, spanning 1997-2018.
The 578 is an ANSI-standardized bulb type, meaning its specifications are governed by a recognized North American standard applicable in both the United States and Canada.
The 578 belongs to the festoon bulb family, a cylindrical form factor that makes contact with its housing through metal end-caps at both ends of the bulb rather than through a base socket.
The 578 festoon bulb has a length of 41mm, which is a critical fitment factor, as festoon bulbs must physically span the contact points of their housing to establish a circuit.
The 578 operates at 12 volts, consistent with the standard electrical system voltage found in conventional passenger vehicles.
The 578 carries a 12-watt power rating, which reflects its energy draw at the rated voltage and is a relevant factor when substituting equivalent LED replacements.
Because the 578 uses end-cap contacts, any replacement bulb must match both the 41mm length and the end-cap contact style to seat correctly in the Ford Expedition dome light housing.