Audi A5 Climate Control System Total Failure Fix

I had a very similar issue with my 2015 Audi A4 last winter. Having some experience with electronic faults in modern cars, I first suspected it was related to the control panel. After troubleshooting, my workshop found that the wiring harness connecting the climate control unit had several damaged connectors. The constant vibration and heat cycles had caused the connection to become loose and corroded. The blower motor itself was perfectly fine, it was purely a connection issue. The fix involved cleaning the connectors and replacing a section of the wiring harness. Total cost was 95 Euro for parts and labor. Since the repair, the climate control system has worked flawlessly. Before suggesting specific fixes for your A5, could you share: Are there any clicking sounds when operating the controls? Does the control panel display work at all? What exact error message appears? Have you noticed any other electrical issues? This information would help determine if your issue matches what I experienced with my A4.

Last service was at 105000 KM, which was just last month. Thanks for sharing your experience. Following up on your questions: No clicking sounds from the HVAC system, The control panel display is completely dead when these issues occur, Error shows AC Malfunction on the main dashboard, Other electrical systems work normally The blower motor makes a faint humming noise when turned to maximum, but no air flows through the vents. Given your description, I suspect it could be a similar wiring issue since the symptoms match closely. Good to know a harness replacement could fix it without needing to replace the entire climate control unit. Did your mechanic have to remove the entire dash to access the wiring, or was it accessible through the glove box area?

Having gone through this exact repair on my A4, accessing the wiring harness for the HVAC system was actually simpler than expected. The mechanic accessed most connections through the glove box area after removing some trim pieces. No full dash removal was needed to reach the electrical connectors. Since your symptoms match mine even closer now, especially the dead control panel display and the blower motor making that faint hum, Im almost certain youre dealing with the same wiring harness issue. The power supply to both the control panel and blower motor gets compromised when these connectors fail. A qualified technician should be able to diagnose this quickly by testing the voltage at specific points in the system. In my case, they found significant voltage drop across the damaged connectors, confirming the diagnosis before starting repairs. Just make sure they specifically check the connection points between the control panel and the main HVAC system unit. The repair should be straightforward and much less expensive than replacing major components like the blower motor or entire control unit.

Based on that information, I will schedule an appointment with my regular mechanic tomorrow. Your experience really helps narrow down the likely cause, especially since your A4 showed such similar symptoms with the HVAC system. The fact that the temperature sensor and control panel issues could be fixed without major component replacement is encouraging. The faint humming from the blower motor suggests its probably still good, just not getting proper power through those electrical connectors. Im relieved this might not require removing the entire dashboard. Will ask them to specifically check the wiring harness and connections near the glove box area first. Hopefully looking at around 100 Euro for a similar fix, which is much better than replacing the whole climate control unit. Thanks for walking me through this, really helped me understand what to expect and what to point out to the mechanic. Will update once I get it checked out.