Audi A4 Turn Signal Bulb Size

The Audi A4 front inner turn signal uses 3357NA, 3457NA, or 2357NA bulb sizes, while front turn signals use 12174NA, 12272NA, or P21W sizes, and rear turn signals use PY21W, 921, or P21W sizes. The replacement bulb chart covers 1996 to 2020 model years with corresponding specifications.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.