The 2013 Audi S4 uses bi-xenon HID headlights with D3S bulbs (35W) in each headlight.
In this model year, the S4 integrates a premium lighting setup rather than a standard halogen system. The headlights are part of Audi’s adaptive lighting package, designed to adjust the beam pattern based on speed, steering, and load, while the bulbs themselves are HID D3S units paired with ballast hardware.
Bulb type and headlight system
Across most 2013 S4 configurations, the main headlights are high-intensity discharge (HID) xenon units. Each headlight houses a D3S 35W bulb, which works with a ballast and projector to produce both low and high beams through a Bi-Xenon mechanism. The Bi-Xenon design uses a movable shield inside the projector to switch between low- and high-beam patterns without a second bulb.
Bi-Xenon explanation
Bi-Xenon means a single HID bulb serves both the low and high beams. The system relies on a mechanical shield inside the projector to create the appropriate cutoff and brightness, offering a compact setup with smooth transitions between beam patterns. This is standard on many Audi performance models of that era and is compatible with Audi’s Adaptive Front Lighting System (AFS).
Replacement and compatibility
Replacing the bulbs requires D3S 35W xenon units and compatible ballasts. For best results, bulbs are often replaced in pairs to maintain consistent brightness and color. If you’re considering upgrades or retrofits (for example, switching to LED), be aware that such changes can affect warranty, regulation compliance, and the overall lighting performance of the vehicle.
Summary
The 2013 Audi S4 is equipped with bi-xenon HID headlights using D3S bulbs (35W) per side, supported by Audi’s adaptive lighting and leveling features. This configuration distinguishes it from stock halogen setups and aligns with the S4’s high-performance, premium lighting design.