Subaru BRZ front turn signal uses 1157 or 7440NA bulb size, while rear turn signal requires 921 or 7440NA bulb size for replacement. The chart covers 2013 to 2023 model 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 7440NA is the most frequently specified bulb across the Subaru BRZ turn signal data, appearing in both the front and rear positions for the 2013-2016 model years. It is a single-filament T20 wedge bulb rated at 12V and 21W, with natural amber glass that produces a yellow-orange output without requiring a separate amber lens or coating.
The natural amber glass of the 7440NA distinguishes it from the clear-glass 7440, which shares the same T20 wedge form factor and wattage. Substituting a clear 7440 in place of a 7440NA would alter the color output of the turn signal, as the amber tint is built into the bulb itself rather than the housing.
The 1157 is specified for the 2023 Subaru BRZ front turn signal and differs fundamentally from the 7440NA used in earlier model years. It is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W main filament and a 5W secondary filament, meaning the socket and wiring configuration for the 2023 front position are not compatible with the single-filament wedge format used in 2013-2016.
The BAY15d bayonet base of the 1157 uses an offset pin design to prevent incorrect insertion, a feature absent from wedge-type bulbs such as the 7440NA and 921. The two filaments in the 1157 allow a single bulb to serve both a steady low-intensity function and a higher-intensity flashing function within one housing.
The 921 is specified for the Subaru BRZ rear turn signal in 2017-2018. It is a single-filament T15 wedge bulb rated at 12V and 16W, making it lower in wattage than both the 7440NA and the 1157.
The rear turn signal position shifted from the 7440NA in 2013-2016 to the 921 in 2017-2018, representing a change in both bulb format and wattage. The T15 and T20 wedge bases are not interchangeable, as the T20 is physically larger, and fitting an incorrect wedge size risks a loose or non-functional connection.
All three bulbs in these specifications conform to ANSI standards applicable in the United States and Canada, indicating they meet a defined set of performance and dimensional criteria for those markets. This standardization means equivalent bulbs from different manufacturers carrying the same ANSI designation are generally interchangeable within the same socket type.
All specified bulbs operate at 12V, consistent with the standard electrical system voltage of passenger vehicles. Wattage varies across the three types, with the 1157 carrying a dual rating of 21W and 5W, the 7440NA rated at 21W, and the 921 rated at 16W.