What is the low beam headlight bulb size for a 1991 Audi 90?

The 1991 Audi 90 uses a 9004 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 1991 Audi 90?

The high beam bulb size for the 1991 Audi 90 is 9004 LED.

Why are my 1991 Audi 90 headlights dim?

Dim headlights on a 1991 Audi 90 can be caused by aging halogen bulbs, which lose brightness over time, or oxidation (cloudiness) on the plastic headlight lenses. Upgrading to a 9004 LED LED conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 1991 Audi 90 fog light?

The 1991 Audi 90 uses a H3 LED bulb for the fog light position.

Is the 1991 Audi 90 single or dual beam?

The 1991 Audi 90 uses a single bulb (dual filament) headlight system. This means one bulb controls both high and low beams.

Can I install LED bulbs on my 1991 Audi 90?

Yes, the 1991 Audi 90 comes with standard halogen bulbs from the factory, but they can be upgraded to LED. You will need a 9004 LED LED conversion kit for the low beams.

Does the 1991 Audi 90 have fog lights?

Yes, the 1991 Audi 90 takes a H3 LED bulb for the fog light position.

How do I change the headlight on a 1991 Audi 90?

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 9004 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 1991 Audi 90?

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 9004 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 1991 Audi 90 headlights?

A pair of halogen 9004 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 1991 Audi 90?

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 9004 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.

This vehicle is part of the 1989–1992 Audi 90 generation. All models in this range share identical light bulb sizes.

Fitment Guaranteed for 1991 Audi 90

What Size Bulbs Does a 1991 Audi 90 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 1991 Audi 90 Have?

Lighting on the 1991 Audi 90 is managed by a total of 12 bulbs, covering everything from primary headlights to signal indicators. It features an extensive lighting system powered by a halogen-based setup where a single 9004 LED dual-filament bulb handles both low and high beam duties within the same reflector. This model belongs to the mid years of the 90's 1989-1995 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 1991 Audi 90?

Upgrading to LED is one of the most effective ways to modernize your Audi's appearance and safety profile. Since your 90 uses a single 9004 LED bulb for both high and low beams, ensure your chosen LED kit is "dual-beam" compatible. This allows the LED circuitry to mimic the two-filament design of the original halogen bulb. 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 H3 LED fog lights; switching these to LED can dramatically improve your visibility in adverse weather.

1991 Audi 90 Bulb Size Chart

Position	Bulb Size	Shop
Low Beam	9004 LED	Buy 9004 LED →
High Beam	9004 LED	Buy 9004 LED →
Fog Light	H3 LED	Buy H3 LED →
Brake Light	70	Buy 70 →
Dome Light	6411	Buy 6411 →
Side Marker	2825	Buy 2825 →
Turn Signal Front	7528	Buy 7528 →
License Plate	3893	Buy 3893 →
Parking Light	7528	Buy 7528 →
Turn Signal Rear	7506	Buy 7506 →
Reverse Light	7506	Buy 7506 →
Trunk Light	6411	Buy 6411 →