Dodge Ram 1500 Back Up Light Bulb Size

The Dodge Ram 1500 back up light utilizes 921, 3057, P21W, and 1156 bulb sizes depending on the specific production version. Available information covers the period from 1994 through 2010.

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
2007-2010	921
2002-2006	3057
1994-2001	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3057
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The Dodge Ram 1500 backup light specifications span model years 1994 through 2010 and reference three distinct bulb sizes: 921, 3057, and 1156.
All three bulb types listed are ANSI standardized for the US and Canadian markets and operate on a 12-volt electrical system.
The 921 is a T15 wedge-base bulb rated at 16 watts. It is specified for the Dodge Ram 1500 across the 2007-2010 model years.
The T15 wedge base means the 921 bulb is held in its socket by the tension of the base itself, with no separate locking mechanism or pins required.
The 3057 is a T25 dual-filament wedge bulb rated at 27 watts on its primary filament and 7 watts on its secondary filament. It is specified for model years 2002-2006.
Because the 3057 carries two filaments at different wattages, it is not directly interchangeable with single-filament bulbs such as the 921 or 1156 without potential fitment or circuit compatibility concerns.
The 1156 uses a BA15s bayonet base, which is a single-contact bayonet mount, and is rated at 21 watts. It is specified for model years 1994-2001.
The BA15s bayonet base of the 1156 differs physically from the wedge bases of the 921 and 3057, meaning the socket design changed at some point in the Ram 1500 production run.
The three bulb types across these model years represent two different base styles, wedge and bayonet, which are not interchangeable with one another regardless of voltage or wattage similarity.
Wattage varies across the three specified bulbs, ranging from 16 watts for the 921 to 21 watts for the 1156 to 27 watts on the high filament of the 3057, reflecting differences in light output and circuit load.