Ford F-150 Dome Light Bulb Size

The Ford F-150 dome light utilizes bulb sizes 578, 912, and 561 depending on the specific production period for the vehicle. Available data covers the span from 1975 through 2014 for the listed components.

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
2004-2014	578
1989-1998	912
1975-1980	561

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V, 12W.	578
ANSI standard (US & Canada). Wedge bulb (T15). Variant of 921. 12V, 12W.	912
ANSI standard (US & Canada). Festoon bulb, 44mm length, end-cap contacts. 12V, 12W.	561

Other Locations

Additional Notes

The Ford F-150 dome light specifications reference three distinct bulb types across the listed model years: the 578, 912, and 561.
The 578 is a festoon-style bulb with a 41mm length and end-cap contacts, operating at 12V and 12W under the ANSI standard applicable in the US and Canada.
The 561 is also a festoon-style bulb with end-cap contacts, though its length is 44mm rather than 41mm, and it shares the same 12V, 12W electrical rating as the 578.
Because the 578 and 561 are both festoon bulbs with end-cap contacts but differ in length, the two types are not interchangeable despite their similar construction.
The 912 is a wedge-style bulb of the T15 form factor, rated at 12V and 12W, and is classified as a variant of the 921 bulb under the ANSI standard.
The wedge-style 912 uses a different contact method than the festoon 578 and 561, making it physically incompatible with sockets designed for festoon bulbs.
The Ford F-150 (2004-2014) uses the 578 bulb for the dome light position.
The 912 bulb applies to the 1989-1998 model years, representing a different bulb type from the one used in later production.
The 561 bulb is specified for the 1975-1980 model years, and its 44mm festoon format distinguishes it from the 41mm 578 used in more recent entries.
All three bulb types share the same 12V, 12W electrical rating, though their physical formats differ in ways that affect socket fitment.