Ram ProMaster Back Up Light Bulb Size

The Ram ProMaster back up light bulb uses 7440 and 921 size specifications across different model configurations. The replacement chart covers vehicle production spanning 2014 to 2024.

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
2024	7440
2014-2023	921

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

Other Locations

Additional Notes

The Ram ProMaster uses two distinct bulb types across its model years for the back up light position: the 921 and the 7440.
The 921 is a T15 wedge bulb rated at 12V and 16W, conforming to ANSI standards applicable in the US and Canada.
The 7440 is a T20 single-filament wedge bulb rated at 12V and 21W, also conforming to ANSI standards applicable in the US and Canada.
The T15 and T20 designations refer to the outer width of the wedge base, expressed in eighths of an inch, meaning the two bulbs are physically different sizes and are not interchangeable.
The 7440 carries a higher wattage of 21W compared to the 16W rating of the 921, reflecting a difference in power draw between the two bulb types.
The Ram ProMaster (2014-2023) uses the 921 bulb for the back up light, spanning ten consecutive model years.
The 2024 Ram ProMaster departs from the 921 specification, requiring the larger 7440 bulb instead.
Because the 7440 and 921 differ in both base width and wattage, substituting one for the other in a given model year would result in an incorrect fitment.