Buick Velite HVAC Failure Linked to Sunlight Sensor

Had the same problem with a 2017 Buick Velite 6 EV at 130k km. The HVAC sensor malfunction showed similar symptoms, inconsistent temperature control and recurring error codes. After fault detection procedures, the issue traced back to a damaged wiring harness connector at the temperature sensor assembly. The automotive sensor wiring had deteriorated where it passes through the firewall, causing intermittent connection issues. This created confusing signals to the climate control module. The repair required replacing the entire temperature sensor wiring harness and recalibrating the HVAC system. While not a major mechanical issue, proper diagnosis was crucial since similar symptoms can point to multiple sensor faults in the climate control network. Key indicators it was the wiring: Error codes appeared more frequently during temperature changes, Climate control behaved erratically regardless of settings, System would sometimes reset itself while driving Would suggest having a complete sensor fault diagnostic test done, focusing on the wiring connections rather than just the sensors themselves. The HVAC sensor network in these models often needs attention around this mileage point.

Thanks for sharing your experience with the sensor fault issue. Your description matches my symptoms perfectly, especially the erratic climate control behavior. Did you remember roughly what the repair cost came to? Also curious if you have had any other temperature sensor problems since getting it fixed? This would really help me budget for the repair, since my daylight sensor and HVAC system are still acting up despite the initial mechanic visit.

Since fixing the solar sensor fault at the shop, my Velite has been running perfectly. The repair was straightforward, they found a faulty cable connection to the daylight sensor that was causing the erratic HVAC behavior. Total cost came to 95 for the wiring repair and reconnection work. No temperature sensor problems have occurred in the past few months. The fault detection system hasnt thrown any new error codes, and the climate control responds normally now. The key was having a proper diagnostic test done to pinpoint the exact connection issue rather than just replacing parts. The HVAC sensor system in these models is actually quite reliable once the wiring connections are properly secured. Based on my experience, getting a thorough diagnostic check is worth it to avoid replacing expensive parts unnecessarily. Interesting that you mention the initial mechanic visit didnt solve it, make sure whoever looks at it next specifically checks the sensor wiring connections, as thats often the real culprit rather than the sensors themselves.

Wanted to update on my HVAC sensor situation, finally got it properly diagnosed and fixed. After reading the advice here, I took it to a different shop that specializes in EV systems. They ran a complete sensor fault diagnostic and found exactly what was described, damaged wiring near the firewall that was disrupting the temperature sensor signals. The repair cost came to 115 total, including the new wiring harness and sensor calibration work. Been about 2 weeks now, and the climate control is working perfectly. No more error codes or issues with the sunlight sensor either. Really glad I pushed for a proper diagnosis instead of just replacing parts. The original mechanic had missed the wiring connection problem completely. For anyone else dealing with similar HVAC sensor issues, definitely worth getting a thorough diagnostic check first.