What are the common issues with the Audi 80's window regulators?

I noticed that my Audi 80's windows are not going up or down smoothly. What could be causing this issue and how can I fix it?

The most common issue with the Audi 80's window regulators is a faulty motor. If you hear a clicking noise when trying to open or close the windows, it is likely that your motor has failed and needs to be replaced. To fix this issue, you can purchase a new motor and replace it yourself or take it to a professional mechanic.