The Lexus GS300 back up light utilizes bulb sizes 921, 7440, 1156, and P21W depending on the specific version of the vehicle. Data for the components covers the range from 1993 to 2006.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lexus GS300 back up light specifications reference three distinct bulb types across its model years: the 921, 7440, and 1156. All three conform to ANSI standards applicable in the United States and Canada and operate on a 12-volt system.
The 921 is a T15 wedge bulb rated at 16 watts. It is the most frequently specified bulb across the GS300 back up light data, covering the 2001-2006 model years in the general back up light position.
The 7440 is a T20 single-filament wedge bulb rated at 21 watts. Its wedge base differs in size from the T15 used by the 921, meaning the two types are not interchangeable despite both using wedge-style bases.
The 1156 is a single-filament bulb with a BA15s bayonet base, also rated at 21 watts. Its bayonet mounting style is physically distinct from the wedge bases of the 921 and 7440, making cross-substitution between these types incompatible.
The outer back up light position on the 2000 Lexus GS300 is split by a production date: vehicles produced through July 2000 use the 7440, while those produced from July 2000 onward use the 921.
The inner back up light position on the 2006 Lexus GS300 specifies the 921 bulb for vehicles produced through July 2006.
The inner back up light position on the 1997 Lexus GS300 specifies the 1156 bulb for vehicles produced through August 1997.
The 7440 and 1156 share the same wattage rating of 21 watts, whereas the 921 draws only 16 watts, reflecting a lower power output relative to the other two types.
The 1993-1997 model years of the Lexus GS300 rely on the 1156 in the general back up light position, representing the earliest bulb type used across the listed specifications.
The 1998-1999 outer back up light position specifies the 7440, which also serves as the general back up light bulb for the same years, indicating consistent use of that type across both positions during that period.