2018 Audi S4 Bulb Size

Misconception: many people think all bulbs for a 2018 Audi S4 are interchangeable or just "any H7" will work. Why it seems true: bulb labels look simple and shops sometimes sell generic packs, so it feels faster to pick something off the shelf. What is true: your Audi S4 uses specific sizes and types for low beam, high beam, fog, turn, and interior lights, and fitment affects brightness, beam pattern, and housing clearance. Implications: using the correct bulb sizes preserves visibility and avoids heat or moisture issues in the housing. Quick tests: check your owner’s manual, compare existing bulb numbers, or use the chart on this page to match sizes. Quick recap: think of it as a small safety step that pays off. Affiliate disclaimer: some links on this page are affiliate links, which may earn me a commission at no extra cost to you.