Audi Door Latch Failure: Alarm & Lock System Malfunction

Had nearly the identical problem with my Audi A6 1999. Based on some experience working on automatic locks and door switches, I can share what worked for me. The car alarm kept going off out of nowhere and the door locks stopped responding correctly. After checking with my workshop, they found the wiring harness connecting to the door sensor was damaged, causing intermittent signal issues with the vehicle doors. The fix involved replacing a section of the wiring and a faulty door switch. Total repair cost was 95 Euro and took about 2 hours to complete. The car sensor system started working perfectly after that, with no more false alarms or lock problems. To help diagnose your specific case more accurately, could you share: Does this happen with all doors or just one specific door, Are there any error codes showing on the dashboard, Did the problem start suddenly or develop gradually, Have you noticed any moisture or water damage around the door area This information would help determine if your issue matches what I experienced with my A6.

Latest service done at 179113KM. Thanks for the detailed response. The electrical issue affects only the driver side door, with no error codes displayed. The problem developed gradually over about 2 weeks, starting with occasional non-response from the key fob, then progressing to complete failure. After inspecting the door area myself, I noticed slight corrosion near the door switch connector, which might explain the car alarm triggering out of nowhere. No visible moisture damage, but the automatic locks sometimes make a clicking sound when attempting to operate. Your repair costs sound reasonable. Did you need any special diagnostic tools to pinpoint the exact location of the wiring harness fault?

Thanks for those extra details. Yes, this definitely sounds similar to what I faced with my A6. The gradual failure pattern and corrosion you mentioned practically mirrors my experience. For diagnosing the wiring harness issue, my mechanic used a basic multimeter to test continuity through the door latch wiring. No specialized diagnostic tools were needed. The clicking sound from the automatic locks was also present in my case, it typically indicates the system is receiving power but has a break in the signal path. The corrosion you found near the door switch connector is a telltale sign. In my case, this corrosion had worked its way into the wiring harness, creating intermittent contact issues that triggered the car alarm out of nowhere. Once moisture gets in there, it slowly deteriorates the connections. A tip from my repair: They also applied dielectric grease to the new connections to prevent future corrosion issues. Since then (about 18 months now), the vehicle doors have functioned perfectly with no false alarms or locking problems. Given the similarities, I expect you're looking at a similar repair scope. The door latch assembly itself seems fine since you mentioned the mechanical operation works, it's likely isolated to the electrical components and wiring.

That makes a lot of sense about the dielectric grease application. I checked the door switch connector again today and the corrosion appears worse than I initially thought. The contact signal definitely seems compromised. Based on your experience, I will schedule a repair this week and request they check the entire wiring harness on the driver side door. The 95 Euro cost seems fair for the work involved. It is reassuring to know special diagnostic equipment likely will not be needed. The gradual failure of my door sensor matches your situation exactly, and the clicking from the automatic locks confirms we had the same electrical issue. Hopefully adding dielectric grease during the repair will prevent future problems with the vehicle doors. Will update once the work is completed, sounds like I can expect about 2 hours of labor time. Really appreciate you sharing your repair experience in such detail. This helped narrow down the problem and gave me confidence it is fixable without major cost.