Audi A3 Headlight Bulb Size

Additional Notes

• The D3S bulb is the most widely specified HID type across the Audi A3 headlight data, appearing in both high beam and low beam positions for model years 2009-2018. It operates at 42V and 35W, uses a PK32d-5 base with an integral ignitor, and is a mercury-free discharge bulb designed exclusively for projector-type housings.
• The H7 bulb is the most frequently listed halogen type in these specifications, covering high beam and low beam roles across multiple years. It is a single-filament bulb rated at 12V and 55W with a PX26d base, and holds approval under ECE standards as well as in the United States and Japan.
• The 2006-2008 Audi A3 low beam positions list up to four distinct bulb types per year, including D1S, D2S, H8, and H11, reflecting a notably high degree of headlamp system variation within a single model year.
• The D1S and D2S bulbs, specified for 2006-2008 low beams, both operate at 85V and 35W, which is substantially higher than the 42V operating voltage of the D3S, D4S, and the 12V of the D5S. The D2S requires an external ignitor, while the D1S incorporates the ignitor within the bulb itself.
• The H15 bulb, listed for the Audi A3 high beam position in 2014-2016 with halogen capsule headlamps, is a dual-filament type rated at 12V with a 55W main filament and a 15W secondary filament. Its PGJ23t-1 base is not shared by any other bulb type in these specifications, making it non-interchangeable with other halogen types listed here.
• The D5S bulb, specified for 2019-2021 HID high beam and low beam positions, operates at a significantly lower voltage and wattage than other HID types in these specifications, rated at 12V and 25W. Its PK32d-7 base is unique among the discharge bulbs listed and is not compatible with housings designed for D3S or D4S fitment.
• Several years in the specifications list both an HID bulb type and a halogen alternative for the same beam position, indicating that the headlamp system installed on a given vehicle determines which bulb applies. Substituting one type for the other is not supported by the fitment data, as each corresponds to a distinct and incompatible housing design.
• The H8 bulb appears in both high beam and low beam positions across multiple years, though its application context differs. In 2006-2008 high and low beam entries it is associated with bi-xenon headlight systems, while in 2019-2021 high beam entries it is paired with the D5/D7 gas discharge system as a halogen complement. It is a single-filament bulb rated at 12V and 35W with a PGJ19-1 base.