The Lexus LS600h back up light requires a 921 bulb size for proper installation and function within the rear lighting assembly. Data for the specific component covers the period from 2008 through 2012.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lexus LS600h uses the 921 bulb for the standard back up light across the 2008-2012 model years.
The 921 is an ANSI-standard wedge bulb in the T15 form factor, rated at 12V and 16W.
The T15 designation refers to the bulb's tubular shape, with the number indicating its width in eighths of an inch, making it a relatively compact single-filament wedge type.
The inner back up light on the LS600h requires the 3057 bulb across the same 2008-2012 model years.
The 3057 is a dual-filament wedge bulb in the T25 form factor, rated at 12V with a 27W/7W output, where each wattage corresponds to one of its two filaments.
The T25 form factor is physically larger than the T15, meaning the 921 and 3057 are not interchangeable despite both being wedge-base bulbs operating on 12V.
The dual-filament design of the 3057 allows it to serve two lighting functions within a single housing, which is why it is specified separately for the inner back up light position.
Both the 921 and 3057 conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances for those markets.