Toyota Yaris iA high beam and low beam headlight bulbs both use a 9003 size. The replacement chart covers 2017 to 2018 model years with bulb specifications for each production interval.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 9003 bulb is a dual-filament halogen type that operates on two separate filaments within a single housing, one for high beam output and one for low beam output.
Because the 9003 bulb serves both beam functions, the Toyota Yaris iA uses a single bulb per headlight assembly to handle both high and low beam operation across the 2017-2018 model years.
The 9003 bulb is electrically and physically equivalent to the H4 bulb, a designation more commonly used in European markets, meaning the two types are interchangeable in most applications.
The 9003/H4 bulb uses a three-pronged connector, which is a distinct fitment characteristic that differs from single-filament bulbs such as the 9005 or 9006, making those types incompatible with the Yaris iA headlight socket.
Standard 9003 halogen bulbs typically operate at 60 watts on the high beam filament and 55 watts on the low beam filament, running on a 12-volt vehicle electrical system.
Replacement bulbs for the 2017-2018 Yaris iA headlights must conform to the 9003 base type to ensure proper fitment within the headlight housing and correct connection to the vehicle wiring harness.