The Mazda RX-8 turn signal utilizes a 7440NA bulb size for the front and rear lighting components. Data provided for the specific vehicle covers the range from 2004 to 2008.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mazda RX-8 turn signal specifications cover model years 2004-2011 and apply to both the front and rear turn signal positions.
Two bulb types appear across the full production span of the RX-8: the 1157NA and the 7440NA, both conforming to ANSI standards for the US and Canadian markets.
The 7440NA is a single-filament wedge bulb of the T20 type, rated at 12V and 21W, and fitted in natural amber glass to produce the amber color required for turn signal use without relying on a colored lens.
The 1157NA is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with filaments drawing 21W and 5W respectively, also in natural amber glass.
The dual-filament design of the 1157NA means it is capable of serving two independent lighting functions from a single housing, which distinguishes it electrically from the single-filament 7440NA.
The RX-8 (2004-2008) uses the 7440NA in both the front and rear turn signal positions, while the 2009-2011 model years use the 1157NA in both positions.
The 1157NA uses a BAY15d bayonet base, whereas the 7440NA uses a wedge-type base. These two base types are physically incompatible, and one bulb cannot be substituted for the other without a socket adapter or housing modification.
Although both the 1157NA and 7440NA share a 21W rating on their primary filament and operate at 12V, the difference in base type and filament count makes them non-interchangeable between the two RX-8 production periods.