Ford F-250 Super Duty Map Light Bulb Size

The Ford F-250 Super Duty map light utilizes 906 and 578 bulb sizes depending on the specific production period for the vehicle. Available information covers the range from 1999 through 2016 for the components listed in the provided data.

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
2011-2016	906
1999-2010	578

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 8W.	906
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V, 12W.	578

Other Locations

Additional Notes

The Ford F-250 Super Duty map light uses one of two bulb types depending on the model year: the 906 for 2011-2016 and the 578 for 1999-2010.
Both the 906 and 578 are ANSI-standardized bulbs recognized in the US and Canada, meaning they conform to defined electrical and physical specifications rather than being proprietary Ford parts.
The 906 is a T10 miniature wedge bulb, which uses a wedge-shaped base that friction-fits directly into a socket without a separate metal cap or pins.
The 578 is a festoon-style bulb with a 41mm length and end-cap contacts, meaning it seats by pressing its two metal end caps against spring-loaded contacts inside a cylindrical housing.
The 906 operates at 12V and 8W, while the 578 operates at 12V and 12W, making the 578 a higher-wattage bulb despite both running on the same vehicle voltage.
Because the 906 and 578 use fundamentally different socket types, a wedge socket and a festoon socket respectively, the two bulbs are not interchangeable with each other.
The socket type changed between the 2010 and 2011 Ford F-250 Super Duty, which means a replacement bulb sourced for a pre-2011 model will not physically fit a 2011 or later model, and vice versa.