How can I troubleshoot the tail lights on my Audi 80?

I recently noticed that the tail lights on my Audi 80 are not working. I have checked the fuses and replaced any burnt out bulbs, but the issue still persists. Can someone please provide some tips on how to troubleshoot this problem?

First, make sure to check the wiring connections for any loose or damaged wires. It's also a good idea to use a multimeter to test the voltage at the tail light socket. If the voltage is low or non-existent, this could indicate a faulty wiring issue.

Another possible cause for the tail lights not working is a faulty switch. Check the switch for any signs of wear or damage and consider replacing it if needed. It's also important to test the continuity of the switch using a multimeter.

Sometimes, the issue can be with the ground connection for the tail lights. Ensure that the ground wire is properly connected and not corroded. You can also use a test light to check for proper grounding.