The Lexus SC300 back up light utilizes 7440, P21W, and 1156 bulb sizes depending on the specific version of the vehicle. Available data for the bulb sizes covers the range from 1992 through 2000.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lexus SC300 uses three distinct bulb types across its back up light positions: the 7440, the 1156, and the 7443.
All three bulb types operate at 12 volts and share the same ANSI standardization for the US and Canadian markets.
The 7440 and 1156 are both single-filament bulbs rated at 21W, making them functionally equivalent in power output despite their different base designs.
The 7440 uses a T20 wedge base, while the 1156 uses a BA15s bayonet base. These two base types are not interchangeable, as the mounting and retention mechanisms differ.
The 7443 is a dual-filament T20 wedge bulb rated at 21W and 5W. Its T20 wedge base is physically similar to the 7440, but the 7443 carries an additional filament, which affects its internal pin configuration and electrical compatibility.
Because the 7443 and 7440 share the T20 wedge form but differ in filament count and wiring, substituting one for the other is not supported by these specifications.
The Lexus SC300 back up light transitioned from the 1156 bayonet bulb to the 7440 wedge bulb between the 1996 and 1997 model years.
The 1996 SC300 inner back up light specifies the 1156 bulb with a production cutoff noted as "To 08/1996," indicating a mid-year change within that model year.
The 1997-2000 SC300 inner back up light uses the 7443 dual-filament wedge bulb, while the outer back up light for the same years uses the single-filament 7440.
The 1992-1996 SC300 outer back up light and the 1992-1995 inner back up light both specify the 1156 bulb with its BA15s bayonet base.