The Audi RS4 high beam headlight uses a D1S bulb size, while low beam headlight applications accommodate D1S and H7 bulb sizes. The replacement chart covers 2007 to 2008 vehicle production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The D1S is a high-intensity discharge (HID) xenon bulb operating at 85V and 35W, featuring a PK32d-2 base with an integral ignitor built directly into the bulb body. This integrated ignitor design means the bulb and ignitor are replaced as a single unit, distinguishing it from other HID types that use a separate external ignitor.
The D1S carries ECE certification, indicating compliance with European and international lighting regulations. It is designed exclusively for projector-type housings, and installation in reflector-type housings is not compatible with this bulb type.
The H7 is a single-filament halogen bulb rated at 12V and 55W, using a PX26d base. Unlike the D1S, it holds approval not only under ECE standards but also in the United States and Japan, giving it broader regulatory acceptance across major automotive markets.
For the Audi RS4, the D1S serves as the specified bulb for the high beam headlight across both the 2007 and 2008 model years.
The low beam headlight position for the 2007 RS4 lists the D1S as its specified bulb. The 2008 model year lists both the D1S and the H7 for the low beam position, indicating that two distinct headlight system configurations were fitted to that year.
Because the D1S and H7 operate on fundamentally different electrical systems, 85V HID versus 12V halogen, the two bulb types are not interchangeable. A vehicle equipped with a D1S low beam system requires the associated HID ballast and projector housing, none of which are compatible with an H7 halogen setup.