Hello people For a short time now I have two problems concerning the ventilation: 1. Umflutschalter ohne Funktion If, for example, I press the button to shut off the fresh air supply, the orange LED on the switch lights up, but it still smells like exhaust gases. When switched off, there was a subtle snoring from the ventilation in the old days and a swell of fresh air came from the upper ventilation nozzles. Now nothing happens when switching off. Where can the defect lie? Is the mechanical or electronic nature? How can it be diagnosed? 2. Exhaust smell from ventilation For about a month I have been feeling that during the journey between there is a swall of burnt oil odor in the interior. At first I thought that this came from a vehicle running ahead, but it also occurred when I was travelling all alone on a road. I would not be aware that my car would burn oil and smoke/ruze into the interior. At first I thought that it was from a previous vehicle, but when I was travelling on a road alone, I could also be helpful to have a look at the filter.