The Toyota Yaris iA front turn signal requires a 7443NA bulb size while the rear turn signal uses a 7440NA bulb size. Replacement specifications in the chart cover 2017 to 2018 vehicle production years.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Toyota Yaris iA uses the 7443NA bulb for the front turn signal across the 2017-2018 model years. This is a dual-filament T20 wedge bulb rated at 12V with a 21W main filament and a 5W secondary filament, housed in natural amber glass.
The rear turn signal on the 2017-2018 Yaris iA takes the 7440NA bulb, a single-filament T20 wedge type rated at 12V and 21W, also finished in natural amber glass.
Both the 7443NA and 7440NA conform to ANSI standards recognized in the United States and Canada, meaning they meet a defined set of electrical and physical tolerances for those markets.
The natural amber glass on both bulb types produces an amber output without relying on a colored lens or a painted coating, which is the defining characteristic of the NA designation in these part numbers.
Although the 7443NA and 7440NA share the same T20 wedge base and natural amber glass, they are not interchangeable. The 7443NA carries two filaments while the 7440NA carries one, and substituting one for the other would result in incorrect circuit behavior at the respective position.
The dual-filament design of the 7443NA allows the front turn signal position to serve more than one lighting function, with the lower-wattage 5W filament typically supporting a parking or daytime running light role alongside the 21W turn signal filament.