Oldsmobile Regency Back Up Light Bulb Size

The Oldsmobile Regency back up light requires bulb size 2456 or 2356 depending on the specific version of the vehicle. Data for the bulb sizes covers the range from 1997 to 1998.

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
1998	2456
1997	2356

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, specialty application. 12V.	2456
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V.	2356

Other Locations

Additional Notes

The 1998 Oldsmobile Regency uses a 2456 bulb for the back up light, while the 1997 model year uses a 2356 bulb. These two bulbs are not interchangeable despite both operating at 12V.
The 2456 is a festoon-style bulb, meaning it is cylindrical in shape and mounts by pressing into clips at each end rather than inserting into a socket base. It is classified as a specialty application bulb under the ANSI standard recognized in the US and Canada.
The 2356 uses a BAY15d bayonet base, a two-pin offset base that locks into its socket with a twist. This base type is common in dual-filament automotive applications, where separate filaments serve distinct lighting functions within a single bulb.
The mounting systems of the 2456 and 2356 are fundamentally different. The festoon clip mount of the 2456 and the bayonet socket of the 2356 are physically incompatible, meaning a housing designed for one will not accept the other.
Both bulbs conform to ANSI standards applicable in the US and Canada, indicating standardized electrical and physical tolerances within those markets.