VW Transporter Blower Failure Linked to Air Sensor

A faulty HVAC sensor system caused similar issues on my 2013 VW Passat 2.0TSI. The blower failure started intermittently, then stopped completely. Initial diagnostics pointed to the cabin air sensor, but after testing it turned out to be a damaged wiring harness connecting to the air quality sensor module. The main issue was corrosion in the connector pins where the wiring meets the sensor unit. The auto recirculation system kept defaulting to closed position due to incorrect air quality readings. This required removing part of the dashboard to access the wiring cluster. The repair involved replacing the entire wiring harness and sensor assembly. This was a serious repair requiring specialized diagnostic equipment to properly calibrate the new components. Using non-OEM parts or components from other manufacturers like BMW would likely cause compatibility issues with the VW HVAC control module. Based on your symptoms, recommend having the air quality sensor connections checked first before replacing any components. Water damage in this area is common and can cause similar failures.

Thanks for this information. I had almost identical symptoms with my Transporter, the climate control blower and auto recirculation system stopped working suddenly. The mechanic also found corroded wiring near the air quality sensor, but in my case only needed to repair and reseal the connections rather than replace the full harness. Did this fix end up being a permanent solution for you? Also wondering what the total repair cost was? Mine was around 350€ for the diagnostic work and repair, but I am curious if that was reasonable.

After taking it to the mechanic last week, I can confirm the AUC sensor fault has been completely resolved. They found and fixed a loose plug connection at the odor sensor module, much simpler than initially feared. The blower and auto recirculation are now working perfectly. The total repair cost was only 95€ for cleaning and resealing the cable connections. This was significantly less than your repair since they did not need to do extensive diagnostic work or access the full wiring harness. The HVAC sensor system has been functioning normally since the fix, with no return of the previous issues. Your 350€ cost seems reasonable given they had to do more thorough diagnostic work. In many cases with these sensor faults, it is worth checking the simple connection issues first before replacing major components. The BMW AUC compatibility question is less relevant now since the original VW components just needed proper maintenance rather than replacement.

I finally got my VW Transporter fixed last week. The climate control issue turned out to be exactly what you described. The air conditioning sensor connections were corroded, causing the blower and auto recirculation to malfunction. The mechanic first tested the wiring near the AUC sensor and found water damage had affected the connection points. They cleaned the contacts, applied dielectric grease, and properly sealed the connectors. The entire repair took about 2 hours. Total cost came to 220€, which included diagnostic time and parts. Much better than the 800€ another shop quoted for replacing the entire sensor assembly. The blower now works perfectly and the auto recirculation responds correctly to outside air quality. Really glad I checked here first instead of rushing to replace parts. Saved me both time and money. The BMW AUC compatibility question is no longer relevant since keeping the original VW components was the right solution.