Description

1993 Audi S4 Wiring Diagram – 113 Pages of Factory Specs

Let me tell you something about wiring diagrams. I’ve seen more hacked-together electrical work than I care to remember, and nine times out of ten it’s because someone used an aftermarket diagram that had the wrong wire colors or missing grounds. This 1993 Audi S4 Wiring Diagram from the factory is the only one you should trust when you’re chasing a short or adding a component. 113 pages of OEM data, not some third-party scan.

For the 1992 model year, the Audi S4 1992-1993 Wiring Diagram covers identical ground. If you’re working on an RS4, the Audi RS4 Self-Study Programme Technical Manual goes into engine control module details. For comparison, Audi A3 Wiring Diagram – OEM Fuse Box & Relay Assignments uses the same layout principles.

1993 Audi S4 Wiring Diagram – What’s Inside the 113 Pages

The manual begins with a ‘How to Use Wiring Diagrams’ section on page 1. It shows you exactly how to trace a circuit from the fuse/relay panel through connectors to the component. Every wire size and color is labeled. The standard circuit and terminal designations are illustrated on page 4 so you know what each symbol means. There’s a troubleshooting guide for basic electricity starting on page 5. This is not a reprint – it’s the original Audi document.

How to Read the Diagrams – Page 1 Reference

You start at the fuse/relay panel. Each fuse has a designation and amp rating. For example, position #20 is a 30 amp fuse. The diagram uses current track numbers along the bottom. If a wire continues on another page, the track reference tells you where. Welded connections in the harness are marked. Ground paths are shown from the welded connection to chassis ground. Ignore the aftermarket colored copies you find online – they lose the contrast on the wire stripes. Use a multimeter set to DC volts. Probe the terminals at the relay socket. If you don’t have the factory pinouts from this manual, you’re guessing. And guessing with electrical systems causes blown fuses or melted harnesses. That’s why I only use OEM wiring diagrams.

Troubleshooting Basic Electricity – Pages 4–5

Need to figure out why your coolant fan isn’t coming on? Page 4 gives you the standard circuit designations. The ‘Trouble Shooting Basic Electricity’ section on page 5 walks you through voltage drops, continuity checks, and short circuits. Use a multimeter set to DC volts. Probe the terminals at the relay socket. If you don’t have the factory pinouts from this manual, you’re guessing. And guessing with electrical systems causes blown fuses or melted harnesses.

Fuse/Relay Panel Locations and Terminal Designations

The manual covers the main fuse/relay panel and the auxiliary relay panel. Relay positions are numbered – for example, position #2 for the coolant fan high-speed relay. Terminal designations like 30, 15, 31 are standard Audi numbering. 30 is battery positive, 15 is ignition-switched positive, 31 is ground. The connector at the panel is labeled with a letter and terminal number, e.g., connector D terminal 75a. This level of detail is what you need when you’re chasing an intermittent electrical gremlin.

Why Aftermarket Diagrams Fail You

I’ve had three different aftermarket wiring diagrams show three different pinouts for the same Audi S4 ABS controller. One had the colors swapped. Another left out the ground path. The OEM diagram never lies. It was printed by Audi of America for a reason. When you’re dealing with safety systems – airbags, ABS, engine management – you cannot afford to use a diagram that might be wrong. This factory manual is the only source I trust.

113 pages. That’s the whole electrical system laid out.

Brush up on fundamentals with Automotive Wiring on Wikipedia. The same rules apply to Automotive Wiring in general.

FAQ

Does this manual include torque specifications?

No, it is a wiring diagram manual, not a service manual.

How can I identify a specific wire color from the diagram?

Each wire is labeled with a color code and wire size on page 1. The manual includes a color chart and terminal designations. For example, a red/yellow wire indicates power with a stripe. You need to match the current track number on the diagram to the actual harness. Use the troubleshooting section on page 4 to check continuity. If the wire colors don’t match the aftermarket scan you’re used to, that’s because this is the factory document – the aftermarket often simplifies or gets colors wrong. Always verify with the factory diagram before cutting or splicing.

If you’re wrenching on a 1993 S4, this is the wiring diagram you need on your tablet or printed out. Don’t trust your electrical repairs to a scanned copy from a forum. Get the real thing. Access the Factory Manual now and keep it in your shop.