The Toyota Yaris iA tail light requires a 7443 bulb size for proper installation and function. Data for the specific component covers the range from 2017 to 2018.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Toyota Yaris iA outer tail light requires two distinct bulb types for the 2017-2018 model years: the 12961 and the 7443, each serving a separate lighting function within the same assembly.
The 12961 is a Philips part number designation for a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W. Its low wattage is consistent with a parking or position light role.
The 7443 follows the ANSI standard used in the United States and Canada. It is a T20 dual-filament wedge bulb rated at 12V with filaments drawing 21W and 5W respectively, a configuration typical of combined stop and tail light functions.
The dual-filament design of the 7443 means a single bulb handles two brightness levels within one housing, with the higher 21W filament activating under braking and the lower 5W filament serving as a running light.
The W2.1x9.5d base of the 12961 is a wedge-type connection where the glass envelope itself acts as the retention mechanism, requiring no separate metal base or locking collar.
The T10 and T20 designations refer to the tubular envelope width of each bulb, with T10 measuring approximately 10/8 of an inch and T20 measuring approximately 20/8 of an inch across the glass. These two sizes are not interchangeable with each other.
Because the 12961 carries a manufacturer-specific part number rather than an ANSI code, substitution with equivalent T10 W5W bulbs is possible provided the voltage, wattage, and base type match the original specification.