Dead HVAC Blower in Audi A8, Common Sensor Failure Fix

Had a similar issue with my Audi A6 2017. The blower motor complete failure pointed to a common fault in the control module connection rather than an HVAC sensor problem. The climate control system stopped responding, with no air flow through any vents. Initial diagnosis revealed the cable harness connecting the blower control module had corroded pins. While the auto recirculation and AUC sensor were functioning normally, the main issue was the deteriorated wiring connection. The repair required removing the glove box assembly to access the connection point. The technician found moisture had entered the connector housing, causing corrosion. This is actually a known issue that can develop even with relatively low mileage. The fix involved replacing the entire wiring harness and connector assembly. This was not a quick repair as it required careful removal of interior trim pieces, but it provided a permanent solution. Much better than just cleaning the contacts, which often leads to the same problem returning within months. This repair resolved all climate control functions, including proper blower speed control and temperature regulation. While not the most complex repair, it requires specific diagnostic equipment to properly test the control module signals.

Thanks for sharing your experience. I faced a very similar situation with my A8 last winter. The symptoms match exactly, complete blower failure with the air conditioning sensor and climate control being unresponsive. Quick question, do you remember roughly how much you paid for the harness replacement? In my case, the repair was around 650 Euro including labor but wondering if prices vary much. Also, has everything worked perfectly since the fix or have you noticed any other climate control quirks? The auto recirculation feature on my A8 occasionally acts up now, might need to get the AUC sensor checked as a preventive measure.

Just got back from having this exact issue fixed. The symptoms you described with the blower motor and climate control matched my experience completely. The good news is the repair was much cheaper in my case, only 95 Euro to fix a faulty cable connection at the AUC sensor. The cabin air sensor and auto recirculation are now working perfectly. My air conditioning sensor readings are also spot-on, with no more climate control quirks. The air quality sensor system is performing exactly as it should since the repair. The key was finding a technician who recognized that the BMW AUC system often has these connection issues rather than needing a complete harness replacement. This targeted fix has proven very reliable, no issues whatsoever in the last few months. If your auto recirculation is acting up, definitely get the connections checked first before replacing any components. Often its just corrosion or a loose connection causing these symptoms.

Thanks everyone for the detailed responses. I wanted to share how my repair experience turned out. After taking it to a certified shop, they diagnosed a corroded wiring harness near the cabin air sensor, similar to what others mentioned. The total repair came to 475 Euro including parts and labor. They had to remove several trim pieces to access the connection point where the air quality sensor wiring had deteriorated. The AUC sensor itself was actually fine, it was just getting bad signals due to the damaged wiring. The repair took about 3 hours but solved all my climate control issues. The blower now works perfectly at all speeds and the auto recirculation feature is functioning normally again. I specifically asked them to check all the air conditioning sensor connections while they were in there to prevent future problems. For anyone else facing similar symptoms, make sure to have them inspect the wiring harness first rather than just replacing sensors. It saved me from unnecessarily replacing more expensive components.