What are the common reasons for a malfunctioning air conditioning system in the Audi 80?

I recently noticed that my air conditioning system in my Audi 80 is not working properly. What could be the potential causes of this issue and how can I address them?

One common reason for malfunctioning air conditioning in an Audi 80 is a refrigerant leak. This can be caused by damage to the system or old age. The best solution is to have the leak repaired and the refrigerant refilled by a professional.