How can I fix the cruise control issue in my Audi 80?

I recently purchased a used Audi 80 with a broken cruise control system. The dashboard light turns on when I press the button, but it doesn't maintain the set speed. How can I troubleshoot and fix this issue?

First, check the speed sensor and make sure it is functioning properly. Sometimes a loose or damaged sensor can cause the cruise control to malfunction.

If the speed sensor is fine, then the issue may lie with the vacuum lines. Check for any leaks or cracks in the lines and replace them if necessary.

Another common culprit for cruise control issues in Audi 80s is a faulty control module. Have a mechanic check the module and replace it if needed.