CT6 Hybrid HVAC Control Panel Failure & Error Codes

I had a very similar issue with my 2014 Cadillac ELR Hybrid last winter and have some experience working on basic car maintenance. The symptoms you describe match exactly what I encountered, unresponsive control panel and complete air conditioning failure. After checking the electrical connectors, my mechanic found that the wiring harness connecting to the HVAC control panel had several damaged pins and a loose connection. The repair involved replacing a section of the wiring harness and reseating all electrical connectors properly. The total cost was 95€, mostly covering labor since the replacement parts were minimal. The blower motor and other components were perfectly fine, it was purely a connection issue. The fix completely resolved both the heating and air conditioning problems, and the control panel started working normally again. To help troubleshoot your specific case better, could you share: Does the blower motor run at all when you adjust the settings? Are there any other electrical issues in the car? What error codes is the system showing? Did the problem start suddenly or develop gradually? This information would help determine if youre dealing with the same root cause or if theres something else going on with your CT6.

Just had my latest service at 125343 KM and want to thank everyone who helped diagnose this. The root cause was indeed electrical, a faulty temperature sensor and damaged electrical connectors near the HVAC control module. The mechanic also found corrosion on several connection points that was causing intermittent electronic faults. Total repair cost came to 380€ including parts and labor. The system now works flawlessly, both heating and air conditioning are back to normal. For anyone facing similar issues, make sure your mechanic thoroughly checks all sensor connections and the wiring harness before replacing major components.

Its great to hear you got it fixed! My experience was very similar with corroded connections, though not quite as extensive as yours. The way these systems are designed, even minor connection issues can cause the whole climate control system to malfunction. When my mechanic did the repair on my ELR, he also found some corrosion starting on other connectors in the power supply area near the control panel. He cleaned those as preventive maintenance while doing the wiring harness repair. Your repair cost of 380€ seems reasonable considering they had to replace the temperature sensor along with fixing multiple connection points. My initial repair at 95€ was cheaper because we caught it earlier before the corrosion spread to the sensor. The key learning from both our cases is that electrical issues in the climate control system often start small but can spread if not addressed quickly. Regular inspection of the wiring harness and electrical connections during maintenance can help catch these problems early. Glad to hear your heating and air conditioning are working properly again. These Cadillac HVAC systems are generally very reliable once the electrical connections are sorted out properly.

Thanks for all the feedback on this HVAC issue. After driving about 1000km since the repair, I can confirm the fix was definitely worth the 380€ investment. The temperature sensor replacement and electrical connection repairs completely resolved all the problems. The blower motor responds instantly now, and the control panel is fully responsive. Both the heating and air conditioning work exactly as they should. Looking back, the gradual deterioration of the system performance was likely due to the progressive corrosion of those connections. For reference, the error codes initially stored in the system were related to the temperature sensor malfunction and communication issues with the HVAC control module. Anyone experiencing similar symptoms should definitely have their electrical connections and sensors checked first before assuming major component failure. The thorough diagnostic approach saved me from unnecessarily replacing more expensive parts. This experience shows that even complex HVAC system problems can often be traced back to relatively simple electrical issues.