[Isidore]

Wish I was there, I enjoy these types of repairs.

As Fastspek mentioned, de-pin and replace the wire and the connector:

Trace the burned wire back until it is not burned anymore and remove it, but make sure you have removed all of the damaged length, be generous. Find the correct color(s) wire online to replace with.

Solder or crimp. I crimp with non-insulated connectors personally, and then cover with heat shrink that contains adhesive.

 

[Isidore]

^ The Audi SA that I spoke with (who spoke with the foreman who is an R8 "master technician") said to connect the negative clip to the ground bar, not the battery. Also, the owners manual says the same thing.

Your car is a 2010, mine is 2022, obviously something must have changed in the ensuing 12 years? I'm no expert, but I just don't want to damage my battery

I do not want to start a thing here... but I agree.

In my experience I try NOT to connect to the negative battery terminal directly when jumping a car, or connecting a hard wired charger.

Why?

Voltage spikes can damage the ECM. Does it happen often, no. Does it happen, certainly. In my early years I was awarded a scholarship from one of the big 3 auto mfg's and worked at a service shop through college, 8ish years in all roles. Trust me when I say this phenomenon happens. Grounding through the frame with that many amps shields the electrical system from spikes. Tough to tell a customer who had their vehicle towed in for leaving the headlights on we shorted the ECM attempting to jump it.

The same goes for welding anything on a vehicle, disconnect BOTH sides of the battery, or install an isolator. Again... "your muffler install went great, but your car does not start because we fried the ECM while welding it on."

My hard wired tender port connects directly at the positive side, the negative has an OEM triple square bolt grounding close to the battery where a grounding strap is right near by; but through the frame, through the grounding strap, and then to the battery.

 

[Isidore]

Audi uses Tesa tape on their harness:

Tesa's Most Advanced High Heat Harness Tape 51036 Mercedes, BMW, Audi, VW: Amazon.com: Industrial & Scientific

Tesa's Most Advanced High Heat Harness Tape 51036 Mercedes, BMW, Audi, VW: Amazon.com: Industrial & Scientific

www.amazon.com

My advice would be to start removing tape and go back until you see no physical damage, then go a bit further cutting and checking until you see good clean copper.

To check for short you need a DVOM and start testing continuity between the wires adjacent to the burned one.

Physically the burned wire will be crispy and burned, but internally the damage may go back father than the external damage shows. Bending the wire and listening, feeling for it being "crispy" and tracing it back are your best bets. Literally it could be burned all the way to its next connection, which if that is a just connector, it could go back beyond even that. The entire length of that wire saw the amperage that the short burned section you can see got, the entire run and the component at the end are suspect.

I would leave the battery disconnected until repaired to avoid any further shorts, they may have already occured.

Automotive electronics were a challenge for me until I melted the harness in a Toyota Camy, I learned fast, you will too. Start cutting that harness tape off.