The Lexus SC400 brake light utilizes 7440, 1156, P21W, and 1157 bulb sizes depending on the specific production period. Data for the listed components covers the period from 1992 to 2000.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lexus SC400 brake light specifications cover the 1992-2000 model years across three positions: the standard brake light, the Center High Mount Stop Light, and the Outer Brake light.
The 7440 is a single-filament T20 wedge bulb rated at 12V and 21W. It serves as the brake bulb for the 1997-2000 SC400.
The 1156 is a single-filament bulb with a BA15s bayonet base, also rated at 12V and 21W. It fills the brake position on the 1994-1996 SC400.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W main filament and a 5W secondary filament. It is specified for the brake position on the 1992-1993 SC400.
Although the 7440 and 1156 share the same 12V/21W output rating, they use physically different base types, a T20 wedge and a BA15s bayonet respectively, making them non-interchangeable despite identical wattage.
The 1157 and 1156 share the same bayonet-style mounting family but differ critically: the 1157 uses a BAY15d dual-contact base while the 1156 uses a BA15s single-contact base. Substituting one for the other is not supported by these specifications.
The 921 is a T15 wedge bulb rated at 12V and 16W. It is specified for the Center High Mount Stop Light across all model years of the SC400, from 1992 through 2000, without variation.
The 7443 is a dual-filament T20 wedge bulb rated at 12V, 21W/5W. It is specified for the Outer Brake position on the 1997-2000 SC400, and also on the 1995 and 1996 models up to August 1996.
The 1996 Outer Brake position carries a production date qualifier, with the 1156 applying only to vehicles produced through August 1996. This indicates a mid-year specification change within that model year.
The T20 wedge form factor is shared by both the 7440 and the 7443, but the 7440 is single-filament while the 7443 is dual-filament. These two bulbs are not interchangeable where a dual-filament function is required.