Subaru AC Dead: Temperature Sensor Likely Culprit

Had a similar temperature sensor issue on a 2012 Subaru Legacy 2.5i. The climate regulation system showed identical symptoms, no response from AC controls and check engine light activated. Initial sensor diagnostics pointed to the temperature control module, but the actual problem was a damaged wiring harness connector near the blower motor. The connector had corroded and lost proper contact due to moisture buildup in that area. The repair involved cleaning the connector pins and replacing the wiring harness section. This is typically not a serious repair when caught early, but leaving it unfixed can lead to more extensive electrical system damage. Key checkpoints before visiting a shop: Verify fuse condition for the climate control system, Check if temperature reading shows on the display, listen for the blower motor attempting to engage, Look for visible wire damage near the blower area For accurate diagnosis, proper testing equipment is needed to check the temperature sensor circuit. A qualified shop with experience in automotive climate control systems should perform a complete system scan. Remember that faulty temperature readings can also stem from other components in the climate control network, not just the main sensor.

Thanks for the detailed info about the corroded wiring harness. I actually had nearly identical climate issues with my 2009 R2 last summer. The HVAC sensor reading was completely off and the AC wouldnt respond. Turned out the main climate control module needed replacement along with some wiring repairs. Just wondering, do you recall the total repair cost for your sensor issues? Also has everything worked properly since the fix? Would help me understand if I got overcharged for my repair.

Glad to provide an update on my 2012 Legacy sensor repair. After seeing the mechanic last week, it turned out to be a much simpler fix than initially expected. The HVAC sensor itself was functioning correctly, the issue was traced to a loose cable connection that was causing intermittent temperature reading failures. The total repair only came to 95€, which covered diagnosing and fixing the faulty plug connection to the interior temperature sensor. The climate control system has been working flawlessly since then, with accurate temperature readings and proper AC response. Based on what you mentioned about needing a full module replacement and wiring repairs, your repair costs would naturally be higher since it involved more extensive work. The climate regulation system relies on multiple components working together, so costs can vary significantly depending on which parts require attention. If the sensor diagnostics showed a completely failed control module in your case, replacing it was likely the right call. The important thing is that proper function was restored to the temperature control system.

Thanks everyone for the helpful responses. Wanted to share how my repair situation turned out. Took the car to a new shop after reading the advice here about checking the wiring. The mechanic found multiple issues, a failed temperature sensor, damaged wiring near the blower, and corrosion in the main connector. The sensor diagnostics showed the climate regulation system needed significant work. Total repair came to 450€ which included replacing the sensor, fixing the wiring harness, and cleaning all connection points. Been about 2 weeks now and the climate control is working perfectly. No more check engine light and the AC responds immediately. Temperature readings are accurate again. While the cost was higher than expected, having a properly functioning system is worth it. Much better experience with this shop compared to my previous mechanic. Really appreciate all the detailed feedback that helped me understand the potential issues before going in. Made me feel more confident discussing the problems with the mechanic and understanding the recommended repairs.