Hello, have a 9-3 2.0 T Built. 12.98. I am actually quite satisfied; but have a phenomenon since the latest, which I can not estimate. My ventilation is sometimes very fast and then fall back very quickly into the preset range. Sounds almost like a “puffing”. Pollen filter is changed, blower motor is free and also in the installation area no moisture. I then tried the EPC and asked a few screwdrivers; yield was rather poor. is actually only the assumption that the blower resistance/control unit (5045158) has one away: A) can this be ?? B) if yes, where is the installation location and how to get there best ?? (if possible, detailed description.I found in the HAYNES nix usable) Thanks for your help WOLF