Lexus RX450h Back Up Light Bulb Size

The Lexus RX450h back up light requires a 921 bulb size for proper installation and function within the rear lighting assembly. Available data covers a range from 2010 through 2022 for the specified vehicle and component.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Back Up Light

Years	US Type	EU Type	Shop
2021-2022	921	W16W	Check Price
2010-2019	921	W16W	Check Price

Inner Back Up Light

If US Type and EU Type show the same value, a direct cross-reference for this bulb is not available or the data is insufficient.

Years	US Type	EU Type	Shop
2016-2019	921	W16W	Check Price
2010-2015	3057	3057	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921	Check Price
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3057	Check Price

Other Locations

Additional Notes

The 921 bulb is an ANSI-standard wedge type in the T15 form factor, rated at 12 volts and 16 watts, and is used as a single-filament light source.
The 3057 bulb is an ANSI-standard dual-filament wedge type in the T25 form factor, rated at 12 volts with a two-wattage rating of 27W and 7W corresponding to its two filaments.
The Lexus RX450h back up light uses the 921 bulb across the 2010-2022 model years, with no variation in that position throughout the entire listed range.
The inner back up light position on the RX450h transitioned from the 3057 bulb to the 921 bulb between the 2015 and 2016 model years.
The inner back up light on the 2010-2014 RX450h uses the 3057 dual-filament bulb, while the same position on the 2016-2019 model uses the single-filament 921 bulb, making the two types non-interchangeable despite both being wedge-base designs.
The T15 and T25 designations refer to the tubular bulb body size, with T25 being physically larger than T15, which is a factor in socket fitment.
Both the 921 and 3057 bulbs conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and photometric performance within those markets.
The wattage difference between the 921 (16W) and the 3057 (27W/7W) means the two types draw different amounts of current, which is relevant to circuit compatibility when considering substitutions.