Audi Q3 high beam and low beam headlight bulbs utilize D5S and D3S bulb sizes for optimal illumination performance. The replacement chart covers 2015 through 2018 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.
ECE standard (Europe & worldwide). Mercury-free HID (xenon) discharge bulb with PK32d-5 base and integral ignitor, for projector-type housings. 42V, 35W.
The D5S bulb is an HID (xenon) gas discharge type built to the ECE standard, which governs lighting regulations across Europe and numerous other markets worldwide. It operates at 12V and 25W, making it a low-voltage, low-wattage unit relative to other HID types. Its base designation is PK32d-7.
The D3S bulb is also an ECE-standard HID (xenon) discharge type, but it operates at a significantly higher voltage of 42V and a higher wattage of 35W. It features a PK32d-5 base and incorporates an integral ignitor, meaning the ignition component is built directly into the bulb unit rather than housed separately in the ballast circuit.
The D3S is formulated without mercury, a distinction that carries regulatory relevance in markets with restrictions on hazardous materials in automotive components. The D5S specifications do not carry this designation.
The PK32d-7 base of the D5S and the PK32d-5 base of the D3S are physically distinct and electrically incompatible. Despite both being HID types used in the same vehicle line, the two bulbs are not interchangeable with each other.
The D3S is specified for projector-type headlamp housings. This is a housing-specific requirement, meaning the bulb is matched to the optical design of the headlamp assembly rather than being a universal HID fitment.
For the Audi Q3, the 2016-2018 model years use the D5S for both high beam and low beam positions when equipped with HID headlamps. The 2015 model year uses the D3S in both positions instead.
The shared bulb size across both the high beam and low beam positions in each model year indicates that the Q3's HID headlamp system uses a single bulb type to serve dual functions, rather than separate bulb types for each beam mode.
The HID headlamp condition noted for the D5S fitment years means the D5S specification applies only to vehicles built with that headlamp system. Vehicles from those years without HID headlamps would not use the D5S.