Ford B-600 Courtesy Bulb Size

The Ford B-600 utilizes a courtesy light component requiring 912 or 561 bulb sizes depending on the specific application. Available information covers a time span from 1980 through 1994.

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
1981-1994	912
1980	561

Bulb Specifications

Description	Bulb Size
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 B-600 uses the 912 bulb for its courtesy light across the 1981-1994 model years, with the sole exception of 1980, which uses the 561 bulb instead.
The 912 is an ANSI-standardized bulb recognized in both the United States and Canada, operating at 12 volts and 12 watts.
The 912 follows a T15 wedge form factor, meaning it uses a wedge-shaped base that friction-fits directly into a socket without a separate metal base or pins.
The 912 is a variant of the 921 bulb. While both share the T15 wedge form and 12-volt operation, they differ in wattage, so the two are not always interchangeable in applications where wattage tolerance is strict.
The 1980 Ford B-600 uses the 561 festoon bulb, which is an ANSI-standardized type operating at 12 volts and 12 watts.
The 561 festoon bulb has a 44mm length and makes contact through end-cap terminals at each end of the bulb body, a mounting style physically incompatible with wedge-type sockets.
Because the 912 wedge bulb and the 561 festoon bulb use fundamentally different socket types, the two are not interchangeable despite sharing the same voltage and wattage ratings.