Audi A6 Headlight Bulb Size

Additional Notes

• The H7 bulb is the most frequently specified type across the Audi A6 headlight data, appearing in both high beam and low beam positions across multiple model years and headlamp system types. It is a single-filament halogen bulb rated at 55 watts with a PX26d base, widely used in European vehicle lighting applications.
• The D-series HID (High-Intensity Discharge) bulbs, specifically D1S, D2S, D3S, and D5S, are specified for the Audi A6 across HID-equipped variants spanning 1999-2018. Each suffix letter indicates a distinct igniter and base configuration, meaning these types are not interchangeable with one another despite sharing the same discharge technology.
• The D3S and D5S bulbs are mercury-free HID types, as indicated by the "S" suffix denoting a shrouded arc tube. The D2S, also shrouded, contains mercury. This distinction is relevant to disposal regulations in many regions.
• The Audi A6 (2002-2004) used H7 bulbs in the high beam position of HID-equipped headlamp systems, which is an atypical configuration. In most HID fitments across the broader specification range, the high beam position is served by a dedicated discharge bulb rather than a halogen type.
• The H15 bulb is specified for high beam use in halogen capsule headlamp systems on the 2011-2014 A6. The H15 is a dual-filament bulb that serves both high beam and daytime running light functions within a single unit, distinguishing it from single-filament halogen types like H7 or H1.
• The 9005 and 9006 bulb types, specified for 1995-1998 model years, follow the SAE/ANSI designation system rather than the ECE (European) system used by H-series and D-series types. The 9005 is a high beam bulb and the 9006 is a low beam bulb; neither is interchangeable with the other despite their physical similarity.
• The H1 bulb, a single-filament halogen type with a P14.5s base, is specified in both high beam and low beam positions across various years, though it serves different roles depending on the headlamp system. Its use in the low beam position of halogen systems on the 1999-2001 A6 contrasts with its high beam role in 2006-2008 halogen configurations.
• The 1998 A6 carries two separate high beam specifications: the 9005 for early production units and the H7 for later ones. Similarly, the 1996 low beam position transitions from the 9006 in early production to H1 in late production, reflecting a mid-year headlamp system change within a single model year.
• Across the full specification range, the low beam position of HID-equipped A6 variants progresses through four distinct discharge bulb types: D1S (1999-2001), D2S (2002-2008), D3S (2009-2015), and D5S (2016-2018). Each generation represents a separate base and igniter standard, and substitution between them is not supported by the specifications.
• The 2015-2018 A6 high beam data shows that HID-equipped variants do not list a separate halogen high beam bulb alongside the discharge type, unlike earlier years where halogen and HID fitments each had distinct high beam specifications. The 2015 halogen capsule high beam uses H7, while the HID variant uses D3S, and by 2016-2018 only D5S is listed for HID systems.