Peugeot 406 Automatic Temperature Control Issue

It certainly sounds like a sensor issue. Has the temperature reading on the display become erratic or completely disappeared? Is the climate regulation working at all, or is it just blowing hot/cold regardless of the setting? Have you checked the fuse box for any blown fuses related to the climate control system? Also, what error code are you seeing?

The temperature reading seems stuck, not changing at all. The climate regulation isn't working; it's just blowing hot. I did check the fuses, all seem fine. Regarding the error code, where exactly would I find this in my car?

Given the static temperature reading and the always-hot air, a faulty interior temperature sensor is highly probable, especially with an error code present. While you can try to trace the wiring yourself, I would suggest taking it to a workshop. Diagnosing the exact cable or plug issue might require specialized tools. Be prepared for a bill around 95€ if it's just the sensor or connection.

Thanks for the advice. Took it to the shop, and it was indeed a defective connection to the interior temperature sensor. They fixed it for 95€, and the climate control is working perfectly again.