The Kia Niro front turn signal uses a PY21W bulb size, while the rear turn signal also requires a PY21W bulb size. The replacement chart covers vehicle production years from 2017 to 2024 with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The PY21W is an ECE-standard single-filament amber bulb rated at 12V and 21W, fitted with a BAU15s bayonet base. The BAU15s base uses offset pins, which prevents accidental substitution with other 15mm bayonet types.
The 2357NA is an ANSI-standard dual-filament bulb rated at 12V with a high filament draw of 26.9W and a low filament draw of 8W. It uses a BAY15d bayonet base and natural amber glass to produce its amber output.
Because the PY21W uses a BAU15s base and the 2357NA uses a BAY15d base, these two bulb types are not physically interchangeable despite both being 15mm bayonet formats.
The Kia Niro front turn signal position uses the 2357NA for model years 2017-2022, then transitions to the PY21W on halogen trim vehicles for 2023-2024.
The rear turn signal position uses the PY21W across all listed model years, 2017-2024, though the 2023-2024 entries specify the halogen trim as a condition.
The front and rear turn signal positions share the same bulb type for 2017-2021 and 2023-2024, while the 2022 model year is the only one where the front and rear positions differ from each other.
The 2357NA produces amber light through natural amber glass coating rather than through a tinted housing or an amber-dyed filament, which is a characteristic of the NA suffix in the ANSI designation.
The halogen trim notation on the 2023-2024 entries indicates that non-halogen trim configurations on those model years use a different lighting technology and do not take the PY21W bulb.