Passat Hybrid Blower Dead After Mechanic Visit

The symptoms sound very similar to what happened with my 2017 VW Arteon Hybrid. The complete blower failure combined with flashing AUC sensor indicators typically points to a wiring harness issue near the HVAC control module. In my case, a connector behind the glove box had corroded, affecting both the blower motor and air quality sensor signals. The air conditioning sensor cluster was receiving power but couldn't properly communicate with the blower motor. The mechanic found that moisture had damaged the main connector pins. This is actually a known weak point in several VW models with similar HVAC systems. The repair requires accessing the wiring harness and either cleaning/repairing the connections or replacing the damaged section. While not a severe mechanical issue, it needs proper attention since it affects both comfort and safety functions like defrosting. The flashing air quality sensor warning is a good indicator that the issue is electrical rather than mechanical. Having the wiring harness connection points tested should be the first diagnostic step before replacing any components. Since this happened right after a mechanic visit, they may have accidentally disturbed these connections while working on something else in that area.

Thank you for sharing your experience with the wiring harness. The same exact thing happened with my Passat last winter. The auto recirculation and cabin air sensor system started acting up first, then the blower died completely. I also noticed those strange flashing indicators on the climate control panel. Did you remember roughly how much the repair ended up costing? Also curious if you had any recurring issues with the air conditioning sensor system since getting it fixed?

I got the wiring issue fixed at the shop last month, cost was 95€ total for repairing the faulty cable connection to the AUC sensor. Since the repair, the climate control system has been working flawlessly. The air quality sensor and odor sensor indicators stopped flashing, and the blower runs normally through all settings. The auto recirculation feature is now responding correctly to air quality changes, which confirms the AUC sensor is communicating properly with the climate control module. I had some initial concerns about potential moisture damage causing repeat issues, but everything has remained stable over the past several weeks. The technician mentioned these connector problems are fairly common on our VW models when moisture gets into the wiring harness. Regular inspection of the area behind the glove box can help catch any early signs of corrosion before it leads to complete system failure.

Thanks everyone for the helpful replies. I took the car back to my regular shop yesterday. Just as suspected, they found corroded wiring behind the glove box affecting the AUC sensor connections. The mechanic showed me where moisture had damaged the main climate control harness. Total repair came to 120€, they cleaned all connections, replaced a section of damaged wiring, and sealed everything properly to prevent future moisture issues. The auto recirculation and cabin air sensor are now working perfectly again. No more flashing warnings on the climate control panel and the blower is pushing air through all vents like normal. Really glad it turned out to be just a wiring issue rather than needing to replace the entire HVAC control module. Will definitely keep an eye on that area during future services to catch any early signs of corrosion.