Kia Optima Back Up Light Bulb Size

The Kia Optima back up light utilizes 921, 1156, and P21W bulb sizes depending on the specific version of the vehicle. Available data covers the range from 2001 to 2020.

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
2017-2020	921
2003-2013	921
2001-2002	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 Kia Optima uses two distinct bulb sizes across its model years for the back up light position: the 921 and the 1156.
The 921 bulb is a T15 wedge-base type, rated at 12 volts and 16 watts, and conforms to ANSI standards applicable in the US and Canada.
The 1156 bulb is a single-filament type with a BA15s bayonet base, rated at 12 volts and 21 watts, and also conforms to ANSI standards applicable in the US and Canada.
The BA15s bayonet base of the 1156 and the wedge base of the 921 are physically incompatible, meaning the two bulb types are not interchangeable without a socket adapter or housing modification.
The 1156 operates at 21 watts, which is 5 watts higher than the 921, reflecting a difference in electrical draw between the two fitments.
The Kia Optima (2003-2020) uses the 921 bulb for the back up light, with the exception of the 2014-2016 model years, which are not represented in the specifications.
The Kia Optima (2001-2002) uses the 1156 bulb for the back up light, representing the earlier fitment before the transition to the 921.