Ram 5500 Back Up Light Bulb Size

The Ram 5500 back up light utilizes 7440, 921, and 1156 bulb sizes depending on the specific configuration of the vehicle. Data for the bulbs covers the range from 2011 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
2018	7440 (With Projector Headlamps)
2018	921 (Without Projector Headlamps)
2011-2012	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament wedge bulb (T20). 12V, 21W.	7440
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The Ram 5500 backup light specifications reference three distinct bulb types across the model's covered years: the 7440, 921, and 1156.
All three bulb types conform to ANSI standards recognized in both the United States and Canada.
The 7440 is a single-filament wedge bulb in the T20 form factor, rated at 12V and 21W. It is specified for the 2018 Ram 5500 equipped with projector headlamps.
The 921 is a wedge bulb in the smaller T15 form factor, rated at 12V and 16W. It applies to the 2018 Ram 5500 without projector headlamps.
The 2018 Ram 5500 therefore requires two different backup light bulbs depending on headlamp configuration, and the 7440 and 921 are not interchangeable with each other despite both being wedge-base types.
The T20 (7440) and T15 (921) designations refer to the physical size of the wedge base, with T20 being the larger of the two. This size difference is a primary reason the two bulbs are not cross-compatible.
The 1156 uses a BA15s bayonet base rather than a wedge base, making it physically incompatible with sockets designed for either the 7440 or the 921.
The 1156 is rated at 12V and 21W, matching the wattage of the 7440, though the differing base types prevent substitution between them.
The 1156 is specified for the Ram 5500 in both 2011 and 2012, with no headlamp configuration distinction noted for those years.