Audi S4 2018 Bulb Size
Bulb size chart
This page covers the 2018 Audi S4 and helps you verify bulb sizes by lighting position, so you can match the correct replacement to the right socket. Because the S4 uses LED lighting in many areas, it is especially important to confirm the exact lamp location before ordering any parts.
Use the bulb chart for the 2018 Audi S4 as a position-by-position reference for exterior and interior lights. It includes common service points such as headlights, brake lights, turn signals, license plate lights, interior lamps, and cargo-area lighting, which makes it easier to narrow down the correct fitment for your vehicle.
Fitment can vary by trim, lighting package, market, and body style, so always compare the bulb chart with the equipment actually installed on your car. Some 2018 Audi S4 models use LED assemblies rather than replaceable halogen-style bulbs, and aftermarket LED conversions may require different parts or additional compatibility checks. Before buying, inspect the existing bulb or housing whenever possible, since the installed bulb type is the most reliable way to confirm fitment and avoid ordering the wrong replacement.
FAQ
Does the 2018 Audi S4 use LED bulbs for the headlights?
Yes. The bulb chart for the 2018 Audi S4 lists the headlight high beam and low beam as LED. That usually means the light source is part of an LED assembly rather than a standard replaceable halogen bulb.
Are the brake lights on the 2018 Audi S4 LED?
Yes. The brake light bulb position is listed as LED on this page for the 2018 Audi S4.
What bulb type does the front turn signal use on a 2018 Audi S4?
The front turn signal light bulb is listed as LED. Always confirm the exact housing on your car, since lighting equipment can vary by market and package.
What bulb size is used for the license plate lights?
The license plate light bulb is listed as LED for the 2018 Audi S4. If you are replacing a damaged unit, check whether the issue is the bulb, the module, or the entire lamp assembly.
Are the daytime running lights separate from the headlights on this model?
The chart lists the daytime running light bulb as LED. On many Audi models, the DRL function is integrated into the front lighting design, so the exact service part can depend on the specific headlamp setup.
What is the rear turn signal bulb type on the 2018 Audi S4?
The rear turn signal light bulb is listed as LED. Because rear lamp designs can differ by trim or region, it is smart to verify the installed unit before ordering.
What bulb does the back-up reverse light use?
The back-up reverse light bulb is listed as LED. If the reverse light is not working, check the lamp assembly and connectors as well as the light source.
Is the glove box light replaceable, and what size is it?
Yes. The glove box light bulb is listed as 2821 on this page. That is one of the few positions here with a specific bulb number provided.
Do interior lights on the 2018 Audi S4 use the same bulb type everywhere?
Not necessarily. The chart lists several interior positions such as vanity mirror, dome, map, interior door, trunk or cargo area, stepwell, and glove box lighting, but the exact design can vary. Check each location individually instead of assuming one bulb fits all.
Can I convert my 2018 Audi S4 lighting to aftermarket LEDs?
Some owners do use aftermarket LED conversions, but fitment and compatibility depend on the housing, electronics, and trim level. For best results, match the existing bulb type and check for warning messages, polarity issues, or flicker concerns before purchasing.
Why does the bulb chart show LED instead of a part number for many positions?
For many lighting positions on the 2018 Audi S4, the chart identifies the light source as LED rather than giving a separate replaceable bulb number. In those cases, the service part may be an integrated LED module or assembly instead of a standard bulb.
What should I check before replacing any bulb on my 2018 Audi S4?
First confirm the exact lighting position, then compare the installed bulb or assembly to the chart. Also check whether your car has a specific trim, lighting package, or market-specific setup, since those details can change the correct replacement.