The Lexus SC400 front turn signal uses 1034NA or 1157NA bulb sizes, while the rear turn signal requires 7440 or 1156 bulb sizes. The replacement chart covers 1992 through 2000 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lexus SC400 front turn signal position uses two distinct bulb types across its production years: the 1034NA and the 1157NA, both of which are dual-filament bulbs rated at 12V, 21W/5W with a BAY15d bayonet base and natural amber glass.
The 1034NA and 1157NA are variants of the same bulb family, sharing the BAY15d bayonet base and identical voltage and wattage ratings, which means they are functionally interchangeable in terms of electrical characteristics.
Despite their technical similarity, the 1034NA and 1157NA are listed as separate fitments across different model years of the SC400 front turn signal, so the correct part number for a specific year should be confirmed before installation.
The front turn signal of the SC400 does not follow a consistent pattern by year: the 1034NA was fitted in 1993-1995, 1998, and 2000, while the 1157NA was fitted in 1992, 1996-1997, and 1999.
The rear turn signal position of the Lexus SC400 transitioned from the 1156 bulb to the 7440 bulb between the 1995 and 1997 model years, representing a change from a BA15s bayonet base to a T20 wedge base.
The 1156 and 7440 are not interchangeable, as they use physically different base types: the 1156 uses a BA15s bayonet base while the 7440 uses a T20 wedge base, making socket compatibility a critical factor.
Both the 1156 and the 7440 are single-filament bulbs rated at 12V and 21W, meaning they share the same power draw despite their different physical configurations.
The 7440 is a T20 wedge-type bulb, a format that became more common in later vehicle designs and is not backward compatible with the bayonet-style sockets used by the 1156.
All four bulb types listed across the SC400 turn signal specifications conform to ANSI standards applicable in both the United States and Canada.
The rear turn signal used the 1156 across the 1992-1995 model years, then shifted to the 7440 for the 1997-2000 model years, with 1996 remaining on the 1156.