How to diagnose and fix a faulty tail light in an Audi 80?

One of the tail lights on my Audi 80 is not working. It's not the bulb, as I have already checked and replaced it. What could be causing this issue and how can I fix it?

First, check the fuse for the tail lights to see if it needs to be replaced. If that's not the issue, it could be a wiring problem. Inspect the wiring and connections for any signs of damage or corrosion. It's also possible that the problem is with the light switch itself. If none of these solutions work, it may be best to take your Audi to a professional mechanic for further diagnosis and repair.

I had a similar issue with my Audi 80 and it turned out to be a faulty ground wire. Check the ground wire connection for the tail light and make sure it is securely connected. If it's corroded or loose, that could be the cause of the issue. Also, make sure the ground wire is properly grounded to the chassis of the car. Hope this helps!