Hyundai Sonata Back Up Light Bulb Size

The Hyundai Sonata back up light utilizes bulb sizes 921, P21W, and 1156 depending on the specific version of the vehicle being serviced for maintenance. Available information covers a range of production from 1989 through 2023 to assist with identifying the correct components for the lighting system.

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
2016-2023	921
2006-2010	921
1989-2005	1156

Bulb Specifications

Description	Bulb Size
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 Hyundai Sonata uses two distinct back up light bulb sizes across its model years: the 921 and the 1156, both of which are ANSI-standardized bulbs for the US and Canadian markets.
The 921 is a T15 wedge-base bulb rated at 12V and 16W. Its wedge-style base requires no locking pins, as the base itself is pinched into the socket to make contact.
The 1156 is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W. The bayonet mount uses a twist-and-lock mechanism, which is physically incompatible with the wedge socket used by the 921.
The Hyundai Sonata (2006-2023) uses the 921 bulb for the back up light position, with the exception of the 2011-2015 model years, which are not represented in the specifications.
The 1156 draws 21W compared to the 921's 16W, meaning the two bulbs are not electrically equivalent and are not interchangeable despite both operating on a 12V system.
The Hyundai Sonata (1989-2005) uses the 1156 bulb for the back up light position.
The socket type is the primary physical barrier to cross-substitution: a BA15s bayonet base will not seat in a wedge socket, and a wedge base will not lock into a bayonet socket.