What are the common issues in the Audi 80's air conditioning system?

I recently acquired an old Audi 80 and I've noticed that the air conditioning doesn't seem to work properly. Even at its coolest setting, it doesn't blow cold air. How can I troubleshoot this issue and what are some common causes of air conditioning problems in Audi 80s?

One common problem with the air conditioning system in Audi 80s is a refrigerant leak. This can be due to worn out seals or hoses. It's recommended to have a professional mechanic check and fix any leaks before refilling the refrigerant. Also, make sure the cabin air filter is clean and not clogged with debris.