How to fix a broken air conditioning system in an Audi A4?

My Audi A4's air conditioning system stopped working. I can't seem to figure out what's wrong. How can I fix it?

First, check if your car's cabin air filter needs to be replaced. Clogged or dirty filters can cause issues with the air conditioning system. If that's not the issue, then it could be a problem with the compressor or refrigerant levels. It's best to take your car to a trusted mechanic for an inspection and proper diagnosis.

It's possible that the issue is with the thermostat. If the thermostat is not working properly, it can't regulate the temperature in your car. You can try replacing the thermostat yourself, but if you're not familiar with car maintenance, it's best to seek professional help.