Seat Tarraco starting trouble

That sounds like a tricky electrical problem. An interrupted Terminal 30 supply, especially impacting starting, suggests voltage drop issues. Have you checked the battery's resting voltage and its voltage under load when starting? Big voltage drops are a classic symptom. Also, check the wiring harness around the starter motor for damage or corrosion. A short circuit in the wiring could also cause this.

Thanks for the quick reply. How do I check the voltage under load? I have a multimeter, but I'm not sure where to connect it while starting.

A significant voltage drop during cranking suggests a failing battery, or a starter motor drawing excessive current due to wear. Given the age and mileage, the battery could be the issue. But without testing, it's hard to be sure. If you aren't comfortable doing these tests, I suggest taking it to a workshop to avoid electrical faults.

Just to let you know, it was the battery. A replacement fixed the problem. The cost was 290€. Thanks for the assistance.