Volkswagen Atlas Turn Signal Bulb Size

Additional Notes

• The front turn signal positions on the Volkswagen Atlas use two variants of the 12174 bulb family across the 2021-2024 model years, with the 12174NA and 12174SV sharing the same base designation but differing in glass treatment and coating technology.
• The 12174NA is a 12V bulb with natural amber glass, meaning the amber color is produced by the glass itself rather than by a coating or lens filter. It appears in the 2023-2024 front turn signal position.
• The 12174SV is a Philips SilverVision part carrying an enhanced coating over a halogen element, operating at 12V. It was specified for the 2021 front turn signal position, making it a distinct fitment from the 12174NA used in later years despite the shared 12174 base number.
• Because the 12174NA and 12174SV carry different part numbers and coatings, substituting one for the other across model years may not constitute a direct equivalent replacement, even though both operate at 12V.
• The PY21W is an ECE-standard bulb rated at 12V and 21W, fitted with a BAU15s offset bayonet base. The offset pin arrangement of the BAU15s base physically prevents installation of non-offset BA15s bulbs, making base type a critical fitment factor for the 2020 rear turn signal position.
• The 12496 is a 12V halogen bulb classified under a specialty application designation by Philips and Osram. It was specified for the rear turn signal on the 2018-2019 Atlas.
• The rear turn signal position spans three different bulb types across the 2018-2020 model years, with the 12496 used in 2018-2019 and the PY21W used in 2020, indicating these positions are not interchangeable across those years.
• All six bulb specifications across both the front and rear turn signal positions operate on a 12V electrical system, which is standard for passenger vehicle lighting circuits.