Subaru Legacy Door Lock Failure & Random Alarm Triggers

Had similar issues with a 2009 Subaru Outback Diesel. The unusual car alarm triggers and automatic locks failing pointed to a faulty wiring harness in the driver door. The electrical issue was caused by wires getting pinched and frayed where they pass through the door hinge. The main door latch assembly includes critical connections for the central locking system. When these connections degrade, it causes intermittent operation and false alarm triggers. The repair required replacing the complete door wiring harness and door latch mechanism. This was a serious repair since accessing the wiring meant removing the door panel and replacing several components. The job took about 4 hours in the shop. The original diagnosis missed the root cause because the electrical symptoms were intermittent. Worth having a shop check the voltage at the door latch connector and inspect the wiring harness for any visible damage where it flexes. Testing the door switch separately can help isolate whether its the switch or the wiring causing the malfunction.

Thanks for sharing your experience. I am having the exact same symptoms with my Legacy. The door sensor acts up and the automatic locks have a mind of their own. Planning to get it checked based on your suggestion about the wiring harness and door latch assembly. Mind sharing what the total repair cost was in your case? Also curious if you have had any recurring issues since getting it fixed? Want to know what to expect before heading to the shop.

Great update on my Subaru repair situation. After getting it properly diagnosed, the mechanic found and fixed a faulty door contact signal issue. The problem turned out to be much simpler than initially feared, just a loose cable connection in the door wiring harness that was causing the erratic behavior. The total repair cost was only 95€, which included testing the door latch and resolving the connection problem. Much better than more extensive repairs I was worried about. Since fixing that electrical issue, the car alarm system and door locks have worked perfectly. No more unusual triggers or malfunctions. The key was finding a shop that properly tested the electrical connections before jumping to replace major components. Sounds like your Legacy has very similar symptoms to what mine had. Would definitely recommend having them check the wiring connections first before replacing any parts. Let us know how your repair goes. These contact signal problems can be tricky to diagnose but are often fixable without major parts replacement if caught early.

Thanks everyone for the helpful responses. Just wanted to share how my repair situation turned out. Took it to a new mechanic who actually tested the door wiring connections first. Found the issue was a damaged wire harness where it connects to the door latch assembly. Total repair cost came to 180€ including parts and labor, way better than the 400€ I wasted at the first shop. The mechanic showed me where the wires had worn through from years of door movement. They replaced the affected section of the harness and properly secured it. Been about 2 weeks now and the door sensor is working perfectly. No more unusual car alarm triggers or lock issues. Really glad I got a second opinion and found someone who knew what to check. Sometimes the simplest diagnosis is the right one. Worth every cent to have it fixed right this time. If anyone else runs into similar door lock problems, definitely have them check the wiring connections first before replacing major components.