Blower Failure: Troubleshooting Prisma HVAC Sensor Issues

Had the same issue on my 2018 Chevy Malibu last month. The blower failure turned out to be unrelated to the AUC sensor, it was a blown fuse and faulty wiring harness connector at the blower motor. The cabin air sensor and HVAC sensor system were working fine when tested. These sensors typically trigger warning lights when faulty, which wasn't the case here. The main symptom was just a complete blower shutdown, similar to your situation. While not a major repair, it required removing the glove box and partial dash disassembly to access the connection. The wiring harness showed signs of heat damage near the connector. This is apparently a known issue that can develop over time. Worth checking the fuse first, it's the easiest fix if you're lucky. But if the fuse keeps blowing, you're likely dealing with the same wiring harness problem. Definitely get it checked soon, as damaged wiring can cause bigger issues if left unaddressed.

Thanks for sharing your experience. My repair got sorted, and it was indeed the wiring harness causing the issue, not the air quality sensor or any other HVAC sensor components. Would be really helpful to know what repair costs were like at your shop? Also curious if you've had any other blower or AC problems since getting it fixed? The shop mentioned potential issues with the cabin air sensor during diagnosis, but that turned out to be a red herring. Still keeping an eye on the system to make sure nothing else develops.

Great to hear you got it sorted! After my mechanic visit, the AUC sensor fault cleared up completely, turned out it was just a loose cable connection that needed fixing. Total repair cost was 95 € which seems pretty reasonable considering all the dash disassembly work involved. No issues whatsoever with the blower or air conditioning sensor system since the repair. The cabin air sensor and all HVAC components are working perfectly now. It's been running smooth for 3 months straight. The air con shop actually showed me where the wiring harness had gotten damaged, it's a tight spot behind the dash that can trap heat. Regular checks of these connections during servicing can prevent future problems. Sounds like you had the same underlying issue fixed. Keep an eye on the blower performance, but you probably won't see this problem again now that the wiring's been properly secured.

Wanted to update everyone on the final outcome. Just got back from having this fixed at a new shop I found. The repair was straightforward once they identified the actual problem, a damaged wiring harness, not the AUC sensor or climate control system like I initially suspected. Total cost came to €225 including diagnosis and labor. The mechanic walked me through the repair, showing where the wiring had worn through behind the dash. They replaced the entire harness section and secured it properly to prevent future heat damage. The blower's working perfectly now, all fan speeds are back to normal and the auto recirculation feature is functioning as it should. No more worrying about HVAC sensor issues or climate control problems. Big relief it wasn't something more serious with the cabin air sensor system. Just keeping an eye on things for the next few weeks to make sure everything stays working properly, but so far so good.