VW Crafter Cold Start Issue Points to Terminal 30 Fault

I had a similar issue with my VW Transporter T5 2013 diesel. After several frustrating cold starts and multiple cranking attempts, the charging system eventually showed signs of failure. Initial checks pointed toward an electrical fault, but the actual culprit was a heavily discharged battery that was damaging the ignition switch over time. The workshop performed a full diagnostic scan and load test which revealed the battery was only holding about 40% of its rated capacity. The service center traced the entire wiring harness and found the battery was being drained by a small short circuit in the aftermarket radio installation. The complete fix, including a new battery and correcting the wiring, cost 290€. Before suggesting specific solutions for your Crafter, could you share: Does the battery warning light come on while driving? Have you noticed any electrical accessories behaving oddly? Was the battery replaced in the last 3 years? Are there any aftermarket electrical installations? These details would help determine if your issue matches the pattern I experienced with my T5.

Since my last service 3 weeks ago, the battery warning light has been flickering intermittently while driving. The voltage drop seems more pronounced during cold starts. The mechanic did check the starter motor connections but found nothing obvious. The original battery is still installed and none of the aftermarket devices were touched during service. When testing with a multimeter, Terminal 30 shows inconsistent voltage readings ranging from 10.8V to 12.4V. The ignition switch feels normal, but sometimes there is a slight delay between turning the key and the circuit breaker engaging. I will test the battery load capacity tomorrow and report back with the readings.

The battery warning light and voltage fluctuations you describe match exactly what I experienced before discovering the root cause in my T5. Those Terminal 30 voltage readings are definitely concerning and indicate either a failing power supply system or a parasitic drain. The delay in the ignition switch response combined with inconsistent voltage strongly suggests the issue may be compounding. In my case, the low voltage was making the starter motor work harder than necessary, which eventually started affecting other electrical components. Before replacing parts, I recommend these immediate checks: Test all fuse box connections related to the charging circuit, Clean and secure the battery terminals, Measure voltage at the alternator output, Verify the ground straps are tight and corrosion-free The original battery being still installed is noteworthy. A 2011 battery is well beyond its expected lifespan, and cold weather will expose its weakness. My T5s battery showed similar symptoms before complete failure. The flickering warning light typically indicates alternator issues, but given our similar experiences, I suspect the battery is the primary culprit, with the ignition switch and starter motor suffering collateral stress from the voltage inconsistency. A load test will be very telling, when my battery was tested, it showed a significant capacity drop under load, even though the resting voltage appeared adequate.

Thanks for the detailed response regarding the alternator output and ground connections. I performed the voltage tests as suggested, and the results are concerning. The load test confirmed what you suspected, the battery is only maintaining 45% capacity under load, despite showing acceptable voltage at rest. The alternator output fluctuates between 13.2V and 13.8V while running, which seems within normal range. However, I discovered corroded ground straps when checking the wiring harness connections near the transmission mount. After cleaning these connections, the circuit breaker engagement improved slightly, but the cold start issues persist. Given that the original battery has served for 12 years, replacing it seems like the logical first step before investigating potential damage to the starter motor or ignition switch. The similarities to your T5 case are striking, especially regarding the progressive nature of the symptoms. I will get a new battery installed and ensure all the electrical fault indicators are properly reset. The flickering warning light gives me confidence we are on the right track with this diagnosis. Will update once the repair is complete.