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

The 1991 Audi Coupe uses a 9004 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 Coupe?

The high beam bulb size for the 1991 Audi Coupe is N/A.

Why are my 1991 Audi Coupe headlights dim?

Dim headlights on a 1991 Audi Coupe 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 conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 1991 Audi Coupe fog light?

The 1991 Audi Coupe typically does not come with factory fog lights in all trim levels. If your vehicle is equipped with them, check the manual as sizes can vary by trim.

Is the 1991 Audi Coupe single or dual beam?

The 1991 Audi Coupe uses a dual bulb headlight system. This means you have separate bulbs for high and low beams.

Can I install LED bulbs on my 1991 Audi Coupe?

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

Did the 1991 Audi Coupe change headlight bulb sizes from the previous year?

No — the 1991 Audi Coupe uses the same bulb sizes as the 1990 model. This configuration has been consistent across the 1990–1991 generation.

Is the 1991 Audi Coupe the first or last year to use 9004 bulbs?

The 1991 Audi Coupe is the last year in the 1990–1991 generation to use the 9004 bulb for the low beam headlight.

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

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 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 Coupe?

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 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 Coupe headlights?

A pair of halogen 9004 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 Coupe?

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 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 1991 Audi Coupe is the last model year to use this bulb configuration (1990–1991).

Fitment Guaranteed for 1991 Audi Coupe

What Size Bulbs Does a 1991 Audi Coupe 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 Coupe Have?

When it comes to nighttime visibility, the 1991 Audi Coupe relies on an arrangement of 6 specialized bulbs. It features a standard lighting system powered by a dual-bulb halogen configuration using separate 9004 low beam and high beam bulbs for precise light distribution. This model belongs to the late years of the Coupe's 1981-1991 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 Coupe?

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 9004 low beams, as they see the most use. Adding a matching 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.

1991 Audi Coupe Bulb Size Chart

Position	Bulb Size	Shop
Turn Signal Front	7528	Buy 7528 →
Low Beam	9004	Buy 9004 →
License Plate	3893	Buy 3893 →
Brake Light	7528	Buy 7528 →
Parking Light	7528	Buy 7528 →
Tail Light	7528	Buy 7528 →

How do the 1991 Audi Coupe's bulbs compare to other years?

The 1991 Audi Coupe uses the same bulbs as the 1990 model.

This bulb configuration covers the 1990–1991 model years. ← 1990

Finding the best installation guide...

Other Coupe Years

1990 1987 1986 1985 1984 1983 1982 1981

Other Vehicles That Use 9004 Bulbs

2005 Pontiac Montana 2004 Oldsmobile Silhouette 2003 Dodge Ram Van 2003 Dodge Wagon 2002 Mercedes-Benz SL-class 2002 Mercedes-Benz SL500