Solar Sensor Failure Causing HVAC Heat Issues in Chevy

Had the same fault detection issue on my 2012 Chevy Spark. The sunlight sensor malfunction triggered similar symptoms, weak heating and error codes. Initially thought it was the HVAC system, but diagnostic testing revealed a damaged wire harness connecting to the solar sensor. The sensor fault was causing the climate control system to receive incorrect ambient light readings, making it adjust temperature settings incorrectly. The actual fix required replacing the wiring harness and recalibrating the temperature sensor system. Not a major repair in terms of components, but accessing the sensor location behind the dash was time-consuming. Found another interesting connection, the faulty wiring was also affecting other temperature-dependent systems. Once fixed, both the heating performance and automatic climate control worked perfectly again. This type of sensor calibration issue is pretty common in this model series. If you're getting error codes, definitely have the complete sensor circuit checked, not just the solar sensor unit itself. The wiring is often the real culprit.

Thanks for sharing your experience. I just had my 2012 fixed last month with those exact same heating and sensor issues. Definitely sounds like we encountered the same HVAC sensor problem. Would be really helpful to know roughly what you ended up paying for the repair? My bill seemed pretty steep. Also curious if you've had any other sensor calibration quirks pop up since getting it fixed? The daylight sensor on mine is working fine now, but I'm noticing the temperature readings sometimes seem a bit off still. Wondering if that's related or just my imagination.

Quick update on the repair costs, ended up paying 95€ for fixing the faulty cable connection to the solar sensor. Pretty reasonable considering the hassle it was causing. The automotive sensor issue was exactly what we thought, just a damaged connection that needed proper rewiring. Since getting it sorted, the HVAC sensor system's been working perfectly. None of those temperature reading quirks you mentioned, might be worth getting your car sensor system checked again if you're still seeing inconsistent readings. The initial sensor calibration should have taken care of that. The repair completely resolved the heating performance issues and error codes. These sensor faults are really common in our model, but once fixed properly, they usually stay fixed. If your temperature readings are still off, it could be a separate calibration issue with the temperature sensor itself rather than the solar sensor connection. Worth noting that a full car sensor diagnostic would show if there's any remaining calibration problems. Might save you some headaches down the road.

Thanks everyone for the input. Finally took my car to a different mechanic last week and got it properly diagnosed. Turns out the sunlight sensor wasn't the only problem, there was a loose connection in the main temperature sensor wiring harness too. The new shop did a complete fault detection scan and found both issues. Repair bill came to €285 total, €180 for labor and €105 for parts. Took about 2.5 hours to fix everything, including a full sensor calibration. Much better experience this time around. The HVAC sensor is working perfectly now, heating's back to normal and those weird temperature fluctuations are gone. No more error codes either. Definitely worth finding a mechanic who actually took the time to properly diagnose the car sensor system rather than just guessing at the problem. Just glad to have proper heat again now that it's getting colder. Really appreciate all the advice that helped me understand what I was dealing with.