VW Amarok Won't Start: Terminal 15 Circuit Issue Fix

Had this exact same issue with a 2013 VW Tiguan last winter. As someone with moderate car repair experience, I recognize these symptoms immediately. After the car would not start and showed similar error codes, I first suspected the battery but like you, the battery terminals were fine. The clicking starter solenoid was the key indicator that pointed to a power supply interruption. Took it to my regular workshop where they found the root cause, a damaged wiring harness connector near the fuse box. The constant engine vibration had caused one of the main power circuit connectors to work loose over time, creating an intermittent connection issue. The repair involved replacing the damaged connector and securing the wiring harness properly. Total cost was 95€ including diagnostic time. Car has been starting perfectly since then. Before suggesting more specific solutions, could you share: Does the issue happen consistently or intermittently? Are there any other electrical issues like flickering lights? Have you checked all fuses in both the engine bay and interior fuse box? Did any work get done on the car recently before this started? This would help determine if your Amarok is experiencing the same wiring harness issue mine had or if its something else in the ignition circuit.

Had mine serviced just last month at 98940km and started experiencing this exact problem shortly after. Found that the relay switch controlling the starter circuit was faulty, creating an intermittent power supply issue. Testing showed voltage dropping at Terminal 15 when trying to start, which matches your symptoms. The ignition switch was getting power, but the circuit break was happening between the relay and starter solenoid. Worth checking the starter relay first since its a common failure point and much cheaper to replace than a full wiring harness. The clicking sound you describe is typical of a relay switch problem rather than complete harness failure. The problem ended up being less complex than initially feared. A basic relay replacement solved it completely without needing extensive diagnostic work.

Thanks for the valuable feedback on your Amarok repair experience. Your solution makes perfect sense, the relay switch is often overlooked when diagnosing these Terminal 15 voltage drop issues. After replacing my wiring harness connector, the workshop actually discovered a damaged relay switch as well. The defective starter relay was causing similar intermittent voltage issues, even with the new connector installed. Once both components were replaced, the starting problem was fully resolved. The clicking starter solenoid sound can indeed be misleading, in my case, it pointed to the wiring harness, but the underlying relay switch problem was contributing to the circuit interruption. The voltage drop testing was key to isolating both issues. For future reference to others with similar symptoms: 1. Test voltage at Terminal 15 2. Check starter relay switch 3. Inspect wiring harness connections 4. Test starter solenoid operation A basic relay replacement at around 40€ is definitely worth trying before assuming more extensive repairs are needed.

Thanks for sharing that important detail about servicing timing. My previous service visit might have inadvertently contributed to the relay issue, possibly from disturbing connections during maintenance work. The voltage drop at Terminal 15 turned out to be the key diagnostic clue. When testing, we found the ignition switch was receiving proper power, but the circuit break was occurring between the relay and starter solenoid. This matched your experience perfectly. Replacing the starter relay was indeed much more cost-effective than exploring wiring harness issues. The intermittent power supply problem cleared up immediately after installing the new relay. Would have spent unnecessary time and money chasing other potential causes without your input about relay switch failures being a common culprit. For anyone tracking similar symptoms, that distinctive click from the starter solenoid combined with a recent service visit should definitely point toward checking the relay first. The repair ended up being straightforward once we identified the actual problem.