VW Scirocco HVAC: Dead Blower + AUC Sensor Alert

Had the same issue on a 2015 VW Golf GTI. The blower failure combined with flashing auto recirculation indicates two potential problems: either the AUC sensor has failed or there is a wiring issue in the cabin air sensor circuit. In my case, after diagnosis it turned out the cable harness connecting to the AUC sensor was corroded and partially broken. The sensor itself was functioning, but poor connection caused erratic behavior. The fix required replacing the entire wiring harness section and cleaning the sensor housing. This is a known weak point in several VW models. The cabin air sensor and auto recirculation system share common wiring paths, which explains why both systems show symptoms. While not immediately dangerous, driving without proper cabin air circulation can lead to window fogging and reduced comfort. The repair is straightforward for an experienced mechanic with the right diagnostic tools. They need to: Test the AUC sensor functionality, Check wiring continuity, Inspect connector pins for corrosion, Verify blower motor operation Important to have this fixed soon as it affects both comfort and safety systems. The sensor fault can trigger other electronic warnings if left unattended.

Thanks for the detailed response about the sensor fault issue. Your situation sounds identical to mine, especially with the wiring harness problem. Did you remember roughly how much the repair cost in your case? Also curious if the auto recirculation system has worked properly since the fix or if youve noticed any other electrical gremlins popping up? My cabin air sensor seems a bit unreliable even after cleaning so wondering if I should expect more issues down the line.

Just got back from having this exact issue fixed at the shop. The total repair came to 95€ for fixing the cable connection to the AUC sensor. The climate control system has been working flawlessly since then, no more flashing lights or blower issues. The cabin air sensor and auto recirculation are now functioning perfectly. The air quality sensor picks up external pollutants properly, and the system switches between fresh and recirculated air automatically as designed. No other electrical problems have surfaced in the months since the repair. If your cabin air sensor is still acting up after cleaning, it likely needs a proper diagnostic check. These sensors can be sensitive to dirt and moisture, but persistent issues usually point to wiring or connection problems rather than the sensor itself. The repair cost was very reasonable considering how much it improved the overall climate control functionality.

Thanks everyone for the help. Finally took my car to get checked last week. The mechanic found exactly what was described, corroded wiring to the air quality sensor and AUC sensor system. The total fix came to 120€ which included cleaning the entire air conditioning sensor assembly and replacing the damaged wiring section. The auto recirculation is now working perfectly and the blower runs smoothly again. Such a relief to have proper climate control back. The mechanic also showed me the old corroded wiring which explained why the system was acting up. Much better experience than my previous repair shop visits. For anyone else facing similar symptoms, definitely worth getting the wiring checked first before replacing any sensors. The diagnostic process was quick and the fix was cheaper than I expected. No electrical issues since the repair was done.