Jeep Cherokee Back Up Light Bulb Size

The Jeep Cherokee back up light utilizes bulb sizes 7440, 921, 2458, 3157, P21W, 1156, and 199. Available information for the specified components spans from 1974 through 2023.

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
2019-2023	7440
2014-2018	921
1997-2001	3157
1978-1996	1156
1977	199
1974-1976	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). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3157
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Variant of 1156. 12V, 21W.	199

Other Locations

Additional Notes

The Jeep Cherokee backup light specifications reference four distinct bulb types across model years: the 7440, 921, 3157, 1156, and 199. Each carries an ANSI designation valid for the US and Canadian markets.
The 1156 bulb is the most frequently specified type in the Jeep Cherokee backup light application, covering model years 1974-1976 and 1978-1992, and operates on a single filament with a BA15s bayonet base at 12V and 21W.
The 7440 is a T20 single-filament wedge bulb rated at 12V and 21W. It is specified for the 2019-2023 Cherokee and uses a wedge-style base rather than a bayonet mount, making it physically incompatible with sockets designed for bayonet-base bulbs such as the 1156.
The 921 is a T15 wedge bulb rated at 12V and 16W, specified for the 2014-2018 Cherokee. At 16W, it draws less power than the 7440 and 1156, which both operate at 21W, so the two wedge types are not interchangeable despite sharing a wedge base format.
The 3157 is a dual-filament T25 wedge bulb rated at 12V with a 27W high filament and a 7W low filament. It is specified for the 1997-2001 Cherokee. Its dual-filament construction distinguishes it from all other bulb types listed in these specifications, which are all single-filament designs.
The 199 bulb shares the BA15s bayonet base and the 12V, 21W rating of the 1156 and is described as a variant of it. However, the 199 is specified exclusively for the 1977 Cherokee, while surrounding model years use the 1156, indicating the two are not treated as direct substitutes within these specifications.
The wedge-base bulbs (7440, 921, and 3157) and the bayonet-base bulbs (1156 and 199) represent two mechanically incompatible base types. A wedge bulb is held in place by socket tension alone, while a BA15s bayonet base locks into the socket with a twist, so cross-substitution between these groups is not possible without a socket adapter.
The transition from the 1156 bayonet-base bulb to the 3157 dual-filament wedge bulb between the 1992 and 1997 model years reflects a change in both base type and filament configuration for the Cherokee backup light position.
The transition from the 3157 to the 921 between the 2001 and 2014 model years represents a shift from a dual-filament T25 wedge to a single-filament T15 wedge, with a reduction in wattage from 27W to 16W on the primary filament.
The transition from the 921 to the 7440 between the 2018 and 2019 model years involves a change from a T15 to a T20 wedge form factor and an increase in wattage from 16W to 21W, meaning the two bulbs are not interchangeable despite both using wedge-style bases.