What is the low beam headlight bulb size for a 2018 Audi A4?

The 2018 Audi A4 uses a HID-D5S LED bulb for the low beam headlights. We recommend upgrading to LED for better visibility.

What is the high beam headlight bulb size for a 2018 Audi A4?

The high beam bulb size for the 2018 Audi A4 is LED Headlights.

Why are my 2018 Audi A4 headlights dim?

Dim headlights on a 2018 Audi A4 can be caused by aging halogen bulbs, which lose brightness over time, or oxidation (cloudiness) on the plastic headlight lenses. Upgrading to a HID-D5S LED LED conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 2018 Audi A4 fog light?

The 2018 Audi A4 uses a LED Fog Light bulb for the fog light position.

Is the 2018 Audi A4 single or dual beam?

The 2018 Audi A4 uses a dual bulb headlight system. This means you have separate bulbs for high and low beams.

Can I install LED bulbs on my 2018 Audi A4?

Yes, the 2018 Audi A4 comes with standard halogen bulbs from the factory, but they can be upgraded to LED. You will need a HID-D5S LED LED conversion kit for the low beams.

Does the 2018 Audi A4 have fog lights?

Yes, the 2018 Audi A4 takes a LED Fog Light bulb for the fog light position.

Did the 2018 Audi A4 change headlight bulb sizes from the previous year?

No — the 2018 Audi A4 uses the same bulb sizes as the 2017 model. This configuration has been consistent across the 2017–2019 generation.

How do I change the headlight on a 2018 Audi A4?

Turn off the vehicle and open the hood. Locate the headlight assembly from behind, remove the dust cover or retaining clip, disconnect the wiring harness, twist the old HID-D5S LED bulb counter-clockwise to remove it, then insert the new bulb and reassemble. Note: Audi vehicles use a CANbus system, so LED replacements may need an anti-flicker decoder. The whole process typically takes 10 to 30 minutes per side depending on accessibility.

Are LED headlights legal for a 2018 Audi A4?

LED bulbs used off-road or in auxiliary lights are legal everywhere. For on-road headlight use, legality varies by state. Many states allow LED retrofits as long as the beam pattern meets DOT standards. For the best legal compliance, choose a DOT-approved HID-D5S LED LED kit that is designed as a direct replacement and produces a proper cutoff pattern without excessive glare.

How much does it cost to replace 2018 Audi A4 headlights?

A pair of halogen HID-D5S LED bulbs costs $15 to $40, while LED conversion kits run $25 to $60 per pair. If you have a shop do the work, expect an additional $20 to $50 in labor per bulb. Replacing them yourself at home saves the labor cost and usually takes under 30 minutes.

What is the difference between halogen and LED for a 2018 Audi A4?

Halogen bulbs produce a warm yellow light (around 3200K), last 500 to 1000 hours, and draw more power. LED bulbs emit a brighter white light (5000-6000K), last 25,000+ hours, and use less energy. LED upgrades for the HID-D5S LED position are available as direct plug-and-play replacements. Since the Audi uses CANbus monitoring, choose a CANbus-compatible LED kit to avoid dashboard errors.

The 2018 Audi A4 shares its bulb sizes with the 2017–2019 generation.

Fitment Guaranteed for 2018 Audi A4

What Size Bulbs Does a 2018 Audi A4 Use?

Correct headlight, fog light, and tail light bulb sizes. Sourced from OEM catalog data.

Installation Difficulty

Hard (Tight clearances)

Est. Replacement Cost

$15 - $40 (Halogen) / $30+ (LED)

What Lighting System Does the 2018 Audi A4 Have?

Owners of the 2018 Audi A4 will find a total of 9 lighting elements throughout the vehicle's exterior. It features a comprehensive lighting system powered by a dual-bulb halogen configuration using separate HID-D5S LED low beam and LED Headlights high beam bulbs for precise light distribution. This model belongs to the late years of the A4's 1996-2020 production span. Note that Audi vehicles typically feature a CANbus electrical monitor that checks for specific bulb resistance.

LED Flicker Warning

This vehicle is known to use a CANbus system. Installing standard LEDs may cause flickering.

Use a CANbus decoder.

Can You Put LED Bulbs in a 2018 Audi A4?

Upgrading to LED is one of the most effective ways to modernize your Audi's appearance and safety profile. We recommend starting your upgrade with the HID-D5S LED low beams, as they see the most use. Adding a matching LED Headlights LED kit later will complete the look and ensure consistent lighting performance. Because Audi utilizes a CANbus system, standard LED bulbs may cause "bulb out" errors on your dashboard. Always opt for "Error-Free" or CANbus-ready kits which include the necessary resistors. Don't forget the LED Fog Light fog lights; switching these to LED can dramatically improve your visibility in adverse weather.

2018 Audi A4 Bulb Size Chart

Position	Bulb Size	Shop
Low Beam	HID-D5S LED	Buy HID-D5S LED →
High Beam	LED Headlights	Buy LED Headlights →
Fog Light	LED Fog Light	Buy LED Fog Light →
Brake Light	Brake Light Assembly	Buy Brake Light Assembly →
Side Marker	LED Bulb	Buy LED Bulb →
Turn Signal Front	12181NA	Buy 12181NA →
Parking Light	N/A	Buy N/A →
Turn Signal Rear	LED Bulb	Buy LED Bulb →
Reverse Light	LED Bulbs	Buy LED Bulbs →
Trunk Light	LED Light	Buy LED Light →

How do the 2018 Audi A4's bulbs compare to other years?

The 2018 Audi A4 uses the same bulbs as the 2017 model.

The 2019 model continues with the same bulb sizes.

This bulb configuration covers the 2017–2019 model years. ← 2017 2019 →

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Other A4 Years

2020 2019 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996

Other Vehicles That Use HID-D5S LED Bulbs

2019 Alfa Romeo 4C 2019 Alfa Romeo Giulia 2019 GMC Sierra 1500 Limited 2019 GMC Sierra 2500 2019 GMC Terrain 2018 Chevrolet Silverado