The Audi S7 high beam headlight uses D3S, H7, and H8 bulb sizes, while the low beam headlight requires a D3S bulb size. The replacement chart covers 2013 to 2014 production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
ECE standard (Europe & worldwide). Mercury-free HID (xenon) discharge bulb with PK32d-5 base and integral ignitor, for projector-type housings. 42V, 35W.
The D3S bulb appears across both the high beam and low beam positions on the Audi S7 for 2013-2014 when the vehicle is equipped with HID headlamps. It is a mercury-free xenon discharge bulb operating at 42V and 35W, built to ECE standards for use in projector-type housings. Its PK32d-5 base includes an integral ignitor, meaning the ignitor is not a separate component.
The high beam position on the 2013-2014 S7 accommodates three distinct bulb types depending on the vehicle's configuration, while the low beam position is limited to the D3S under HID-equipped variants. This means the high beam circuit has conditional fitment that the low beam position does not share.
The H7 is specified for the high beam position on 2013-2014 vehicles fitted with a cornering light system. It is a single-filament halogen bulb with a PX26d base, rated at 12V and 55W, and carries approval under ECE, US, and Japanese standards.
The H8 is specified for the high beam position on 2013-2014 vehicles without a cornering light system. Although it is also a single-filament halogen bulb rated at 12V, its wattage is 35W rather than the 55W of the H7, and it uses a PGJ19-1 base, which is physically incompatible with the PX26d base of the H7.
The base types across the three bulbs are all distinct: PK32d-5 for the D3S, PX26d for the H7, and PGJ19-1 for the H8. Because the bases differ, none of these bulbs are interchangeable with one another regardless of voltage or wattage proximity.
The presence of cornering lights directly determines whether the H7 or H8 is the correct high beam fitment on halogen-equipped 2013-2014 S7 vehicles. Substituting one for the other would result in a base mismatch, as the two bulbs use incompatible socket types.
The D3S operates at 42V, which is substantially higher than the 12V rating of both the H7 and H8. This voltage difference reflects the fundamental distinction between HID discharge technology and conventional halogen technology, and the two systems require entirely different headlamp housing and ballast configurations.
Both the H7 and H8 conform to ECE standards, and both also carry US approval. The H7 additionally holds approval in Japan, whereas the H8 does not share that approval according to the specifications provided.