Hyundai Elantra Back Up Light Bulb Size

The Hyundai Elantra back up light utilizes 921, P21W, and 1156 bulb sizes depending on the specific production period for the vehicle. Available data for the lighting components covers the range from 1992 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
2021-2023	921
2019-2020	1156
2013-2018	921
2007-2008	921
1999-2003	1156
1992-1995	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 Elantra backup light specifications reference two bulb types across its model years: the 921 and the 1156, both of which are ANSI-standardized 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 bulb is held in place by tension within the socket.
The 1156 is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W. The BA15s designation indicates a single-contact bayonet fitting with a 15mm base width, which is physically incompatible with the wedge socket used by the 921.
The 921 and 1156 are not interchangeable. Their base types differ entirely, meaning a socket designed for one will not accept the other without modification.
The 1156 draws 21W compared to the 921's 16W. Substituting a higher-wattage bulb into a socket rated for a lower-wattage type risks overloading the circuit or damaging the socket housing.
The Hyundai Elantra uses the 921 bulb for model years 2013-2023, with the exception of 2019-2020, which call for the 1156 instead.
The 2019-2020 Elantra requires the 1156 bulb, setting those two years apart from the surrounding model years that use the 921.
Model years 1992-2003 of the Elantra are specified with the 1156 bulb across all listed entries for that period.