Seat Leon outside temperature sensor fault

That sounds like a pain! I had a similar issue with my old car. Have you checked the wiring and plug connection to the vehicle temperature sensor? That's often the culprit and an easy fix. Where is the sensor located in your car?

Good point! I suspected the cable or plug connection might be defective. Do you know if sensor calibration is required after sensor replacement or is it plug and play? Also, any tips on finding the sensor location?

Yeah, a faulty sensor can definitely cause all those issues, especially if it feeds information to multiple systems. I'm not sure about the sensor calibration for your car, but it's worth asking the shop. Honestly, given the symptoms and the potential hassle, sensor diagnostics at a workshop is probably the best bet. They can pinpoint the exact problem and ensure a proper fix.

It was the outside vehicle temperature sensor! I had it replaced at a local shop after sensor diagnostics confirmed it. The replacement cost 95€. Now the air conditioning works, the mirror heating is functional again and I don't have to worry about frozen spray nozzles. Thanks for the help!