Skoda Fabia Outside Temperature Sensor Issue

That sounds like a classic case of a failing outside vehicle temperature sensor circuit. I've seen similar issues on other Skodas and VWs from that era. The air conditioning not working and frozen spray nozzles are definitely linked, as the system uses the temperature reading to prevent damage. Same goes for the mirror heating that is active by temperature monitoring. Have you tried checking the wiring and plug connection to the sensor? Sometimes, a bit of corrosion or a loose connection can cause these problems. Where exactly is the sensor located on your model?

I had a quick look at the sensor itself, but it's a bit fiddly to get to. Do you know of any reliable diagrams or guides showing the exact location and wiring of the outside car temperature sensor for my specific Fabia model and where I can find the vehicle temperature sensor?

Given the symptoms and the age of the car, a faulty connection is highly probable. While you can try to clean the contacts yourself, these connectors can be quite brittle and the sensor itself might be degraded. Since you are not familiar with the sensor’s location and the potential cost is relatively low, my advice would be to take it to a workshop. They can properly diagnose the issue, confirming it's just the connection and not a faulty sensor, and ensure a reliable repair.

The workshop confirmed a faulty connection to the outside temperature sensor. They cleaned the contacts and secured the plug. Everything is working now. The bill came to 95€ as predicted. Thanks for your help!