Laguna poor starting Terminal 30 issue

It sounds as though you are experiencing an electrical anomaly. Is the battery original to the vehicle, or has it been replaced? Furthermore, have you inspected the circuit breaker, wiring harness, and ignition switch for signs of degradation, corrosion, or damage? These elements could contribute to the symptoms you described. Does the vehicle display any warning lights when starting, and have you checked the charging system's voltage output?

Thanks for the quick reply! The battery was replaced about three years ago, so it's not brand new, but shouldn't be totally dead either, right? I haven't checked the circuit breaker, wiring harness or ignition switch yet. To be honest, I wouldn't even know where to start! What would be the easiest way to inspect these things? And where are they located?

Given the age of the replacement battery and your unfamiliarity with electrical systems, I would suggest consulting a qualified automotive electrical technician. Continuously interrupted current to Terminal 30 can be challenging to diagnose without appropriate tools and expertise. Attempting repairs without adequate knowledge could exacerbate the issue or create further complications. The technician will use specialized equipment to check for parasitic drains, faulty wiring, and diagnose issues with individual components.

Okay, thanks for the advice. I suspected it might be beyond my abilities. I took it to a workshop and they confirmed it was a faulty circuit causing the battery drain. Repair cost was 290€. Appreciate the help!