VW Tiguan Terminal 30 Starting Issues Fixed

I had a similar issue with my 2014 VW Touran diesel. Having some experience with electrical systems in cars, I first suspected the starter motor, but it turned out to be more complex. The main power supply was inconsistent due to a heavily discharged battery and corroded connections in the wiring harness near the battery terminal. The workshop performed a thorough electrical fault diagnosis, revealing the circuit breaker was functioning correctly, but the battery was no longer holding charge properly. The complete fix included: Full battery replacement, Cleaning all ground connections, Testing the charging system, Checking the entire wiring harness for damage, Verifying Terminal 30 circuit integrity Total cost was 290€ and the starting problems never returned. Before my repair, I also experienced slow cranking, especially during colder weather. Could you share: Battery age and last replacement date, Whether you notice any correlation with weather conditions, If your battery warning light comes on, Current voltage reading if you have a multimeter This would help determine if your issue matches what I experienced or points to a different electrical fault.

After last service at 59034km, our workshop also identified similar symptoms. They found corrosion affecting the ignition switch wiring, creating intermittent voltage drops in the Terminal 30 circuit. The charging system tested fine, but the wiring harness showed signs of wear near the starter motor connection. Our fix involved: Cleaning all terminal connections, Replacing damaged wiring sections, Installing protective covering on exposed harness areas, Testing circuit continuity Total repair cost was 180€. The electrical fault was fully resolved and starting has been reliable since. The workshop mentioned these issues are relatively common on our engine type as the wiring ages. I suggest getting the voltage drop tested specifically between the battery and starter circuit. This helped pinpoint our exact issue quickly.

Based on my experience with my VW Touran, this is exactly what happened with my car too. The voltage drop test was crucial in diagnosing the problem. After the initial fixes I mentioned, we also discovered some wear on the wiring harness near the starter motor, just like yours. The charging system was working correctly, but the power supply was being compromised by the deteriorating wiring insulation. Our workshop applied additional protective covering on exposed sections, which prevented further corrosion issues. What really made the difference in my case was the thorough check of the ignition switch wiring. Even after replacing the battery and cleaning connections, there were still occasional slow starts until we addressed the wiring degradation. A key learning from my repair was that electrical fault symptoms can be misleading. While the initial signs pointed to a simple battery issue, the root cause was the compromised wiring affecting the Terminal 30 circuit integrity. Since completing these repairs, my starting problems have completely resolved, confirming that addressing the wiring harness and connection points was the right approach rather than just replacing components.

Thanks for sharing those details about your Touran repair. Your experience matches mine exactly, the electrical fault ended up being wiring-related rather than a component failure. The voltage drop test was key in my case too. The workshop found significant resistance in the circuit breaker connection points, plus corrosion affecting the Terminal 30 circuit near the ignition switch wiring, very similar to your situation. Our repairs were nearly identical: Connection cleaning and protection, Wiring harness repairs, New protective coverings, Full charging system verification Final cost in my case was 180€, matching yours closely. Like you mentioned, these electrical issues seem common as these models age. The most important factor was thoroughly checking all connection points rather than just replacing parts. My car has been starting perfectly for 6 months now. The workshop explained that protecting the exposed wiring was critical for preventing future issues. Really appreciate you confirming that addressing the wiring harness was the right approach rather than just changing the battery or starter.