The Lexus SC430 front turn signal bulb uses 3457NA, 3357NA, or 7440NA size specifications, while the rear turn signal bulb requires 7440NA or 7440 size. The replacement chart covers 2002 through 2010 vehicle production years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 7440NA bulb is the most frequently specified type across the Lexus SC430 turn signal positions, appearing in both front and rear applications across multiple model years.
The "NA" suffix on bulb designations such as 3457NA, 3357NA, and 7440NA indicates natural amber glass, meaning the bulb produces an amber-colored output without requiring an amber lens or housing to achieve the correct signal color.
The 7440 and 7440NA are both T20 single-filament wedge bulbs rated at 12V and 21W, with the only distinction being that the 7440NA incorporates natural amber glass while the 7440 does not.
For the rear turn signal on the Lexus SC430, the 7440NA replaces the 7440 starting with the 2006 model year, meaning the amber glass construction became part of the specification where it previously was not.
The 3457NA, used in the front turn signal for the 2007-2008 and 2010 SC430, is a dual-filament T25 wedge bulb rated at 27W/7W, which allows it to serve two lighting functions simultaneously, such as turn signal and parking light, from a single bulb.
The 3357NA, specified for the front turn signal in the 2006 and 2009 SC430, is a single-filament T25 wedge bulb rated at 27W, making it electrically incompatible as a direct substitute for the dual-filament 3457NA despite sharing the same T25 form factor and natural amber glass.
The T25 and T20 designations refer to the wedge base sizes of the respective bulbs, and these two sizes are not interchangeable, which means front and rear turn signal bulbs on the SC430 cannot be substituted for one another across positions that use different base types.
All bulb types listed across the SC430 specifications conform to ANSI standards applicable to the United States and Canada, indicating a standardized electrical and physical specification shared across those markets.
The front turn signal position on the SC430 uses three distinct bulb types across the 2002-2010 model range, specifically the 7440NA, 3357NA, and 3457NA, reflecting that the front position is subject to greater variation than the rear.
Substituting a single-filament bulb such as the 3357NA into a socket designed for the dual-filament 3457NA would result in only one lighting function operating, as the second filament circuit would have no corresponding element to activate.