Audi A8 Headlight Bulb Size

Additional Notes

• The H7 bulb is the most frequently specified high beam type across the Audi A8 model range, appearing in both halogen-only configurations and as the halogen option in years where HID headlamps were also available. It operates at 12V and 55W, uses a PX26d base, and conforms to the ECE standard, giving it approval across Europe, the US, and Japan.
• The D3S bulb is a mercury-free HID (xenon) type rated at 42V and 35W, with a PK32d-5 base and an integral ignitor built into the bulb body. It is designed exclusively for projector-type housings and is not interchangeable with reflector-type housings. It appears in both high beam and low beam positions on the Audi A8 for model years 2011-2014 when HID headlamps are fitted.
• The D2S bulb is an HID (xenon) type rated at 85V and 35W, with a P32d-2 base. Unlike the D3S, it requires a separate external ignitor and is also restricted to projector-type housings. It is specified for low beam positions across a broad range of model years and for the high beam in 2009-2010.
• The D2R bulb shares the same 85V, 35W electrical rating as the D2S and also requires an external ignitor, but uses a P32d-3 base and is designed for reflector-type housings rather than projector-type housings. The two types are not interchangeable despite their similar electrical characteristics. The D2R appears in the low beam position on the Audi A8 for 2000 and 2002 with HID headlamps.
• The 9005 bulb conforms to the ANSI standard used in the US and Canada rather than the ECE standard, operates at 12V and 65W, and uses a P20d base. At 65W, it draws more power than the H7 (55W) or H8 (35W) halogen types also present in these specifications. It is listed for the high beam position on the Audi A8 for 1997-1999.
• The 2010 Audi A8 high beam position carries three distinct bulb specifications differentiated by VIN range and headlamp type: D2S for one configuration, H8 for VINs 4E-A-000 001 through 4E-A-020 000, and H7 for VINs 4H-A-000 001 through 4H-A-010 000. Selecting the correct bulb for this model year requires confirming the vehicle's VIN prefix and headlamp type before purchase.
• Several model years list multiple bulb sizes for the same position depending on whether the vehicle was equipped with HID or halogen headlamps at the factory. Because HID and halogen systems use fundamentally different operating voltages and ignition requirements, the bulb types are not interchangeable between headlamp system types regardless of physical fit.
• The H1 bulb, specified for low beam halogen configurations on the Audi A8 from 1997-2003, uses a P14.5s single-pin base and operates at 12V and 55W. Although its wattage matches the H7, the two bulbs use different base designs and are not interchangeable with each other.