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Guide to the Horn on Your 1970-1972 Audi Super 90

Here is what you need to know about diagnosing and replacing a faulty horn on your classic Audi Super 90.

4 minutes to read 1970-1972 Audi Super 90
Difficulty
1/5
Est. Time
0.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$50-$100
⚠️ Drivable, but... — You can drive the vehicle, but a functioning horn is a critical safety feature and may be required by law for inspections.
Key Takeaways
  • Horn failures on a 1970-1972 Audi Super 90 are common and usually easy to diagnose.
  • Always check the fuse and relay before replacing the horn unit itself.
  • Aftermarket horns from brands like Standard Ignition or Replacement are reliable and affordable solutions.
  • Replacing the horn is a simple DIY job that typically takes less than an hour with basic tools.
The horn on your 1970-1972 Audi Super 90 is a critical safety device. It is a simple but essential part of your vehicle's electrical system. When you press the horn button on the steering wheel, it completes a circuit, sending power through a relay to the horn itself. The horn contains a diaphragm that vibrates rapidly to create the sound, warning other drivers and pedestrians of your presence. On a classic car like the Super 90, the horn system is straightforward, consisting of the horn button, a fuse, a relay, wiring, and the horn unit.

Is Your Audi Super 90 Horn Not Working?

A silent horn is a common issue on vintage cars like the 1970-1972 Audi Super 90. Due to their typical location behind the front grille, horns are exposed to weather, road dust, and moisture, which can lead to corrosion and failure over time. Fortunately, troubleshooting the problem is usually straightforward.

Common Symptoms of Horn Failure

  • No Sound: The most common symptom. When you press the horn button, nothing happens. This could be caused by a blown fuse, a bad relay, a failed horn unit, or a problem with the switch in the steering wheel.
  • Weak or Muffled Sound: If the horn sounds quiet or muffled, it could be due to a poor electrical connection, a bad ground, or a failing horn unit. Sometimes, water getting inside the horn can also cause a distorted sound. Many classic cars have two horns (high and low tone), and if one fails, the sound will be noticeably weaker.
  • Horn Stays On: A horn that won't turn off is typically caused by a stuck horn relay or a short in the horn button switch.

Start with the Simple Things

Before assuming the horn unit itself has failed, always check the fuse box first. A blown fuse is the simplest and cheapest fix. If the fuse is good, listen for a 'click' from the horn relay when you press the button. If you hear a click, the relay and horn switch are likely working, and the problem is probably the horn unit or its wiring. If you don't hear a click, the issue is more likely the relay or the horn switch.

Choosing a New Aftermarket Horn

Finding an original OEM horn for a 1970-1972 Audi Super 90 is nearly impossible. Aftermarket horns are the go-to solution, offering a reliable and affordable fix. They are typically designed as universal or direct-fit replacements that work with your car's 12-volt system. Here’s a look at the brands available.

Brand Tiers

  • Standard Ignition: A well-known and respected brand in the aftermarket industry, Standard Ignition (also known as SMP) has been around for over 100 years. They produce a wide range of quality electrical parts designed to meet or exceed original specifications. Choosing a Standard Ignition horn generally ensures a good fit and reliable performance. For the best sound, it's often recommended to replace high and low-tone horns as a pair.
  • Replacement: This is often a generic or store-brand name for parts that prioritize low cost. While they are designed to fit and function like the original, they are a budget-friendly option. For a simple component like a horn, this can be a perfectly acceptable choice if cost is your main concern.

Aftermarket Horn Cost (1970-1972 Audi Super 90)

PartPrice Range
New Aftermarket Horn$36.29 - $57.52

Note: Prices are estimates and may vary based on the specific brand and retailer.

Frequently Asked Questions (FAQ)

Is replacing the horn on my Super 90 a DIY job?

Yes, for most owners with basic tools, this is a very feasible DIY task. The horn is typically located behind the front grille and is held on by a single bolt. The process involves disconnecting the battery, unplugging the electrical connector, unbolting the old horn, and installing the new one.

Do I need a high-tone or low-tone horn?

Many cars of this era used a dual-horn setup with one high-tone and one low-tone horn to create a fuller sound. If your car has two horns, it's best to replace them in pairs to maintain the original sound character. If you only have one, either a high or low tone will work, but a universal horn is also a common replacement.

What are the most common reasons a horn fails on a classic car?

The top causes are failure of the horn unit itself due to internal corrosion from moisture, a blown fuse, a faulty horn relay, bad wiring or ground connections, or a problem with the horn button in the steering wheel.

My new horn sounds weak. What could be the problem?

A weak sound from a new horn is almost always an electrical issue. Check for poor grounding or corroded wiring. The horn needs a solid ground connection and full voltage to operate at its intended volume. Ensure all connections are clean and tight.

Technical Specifications

Voltage: 12V

Wrenchy
Article researched & written by
Go-Parts' AI research assistant. Every article is backed by live web research, verified OEM data, and real technician knowledge — so you get accurate, up-to-date information you can trust.
Meet Wrenchy → Updated Jul 21, 2026

The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.

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