Madhouse

Hi all, I’m dealing with a long-term battery drain issue on my car and I’m honestly running out of ideas. I’d really appreciate any advice or similar experiences. Car: Skoda Octavia Mk3 (2015), 1.6 TDI Bought in 2016 with ~160,000 km ProblemThe battery keeps draining randomly. It has happened 3 times in the last 2 weeks, but it’s been an ongoing issue for a longer time. Important detail: The issue did NOT happen when I first got the car It started after a few years of ownership It has happened on multiple batteries It even happened on the current battery shortly after it was new BatteryCurrent battery: Banner, ~2 years old (correct spec) Charging system tested → OK UsageCar is used daily Mostly short trips now, but the issue also occurred when driving ~100 km daily What we’ve already checked1. Cooling fan suspicion Radiator fan sometimes ran 20–30 minutes after shutdown (very loud, full speed) Fan was completely disconnected for testing → battery still drained So fan is likely NOT the cause. 2. Charging system Checked in service → OK Other possibly relevant detailsCar is second-hand (unknown modification history) Zeder mechanical immobilizer installed (with electronic buzzer) FM Bluetooth transmitter (always unplugged after driving) Retrofitted multifunction steering wheel: buttons don’t work likely not properly connected / coded License plate light issue (one not working properly) Constant tire pressure warning (probably unrelated) My suspicionI’m thinking it could be: Parasitic drain from aftermarket electronics (GPS tracker, old alarm, etc.) Something that doesn’t go to sleep properly Wiring issue from previous owner Next step plannedMeasure parasitic draw after the car goes to sleep Pull fuses one by one to isolate the circuit QuestionsHas anyone experienced something similar on Octavia Mk3? Any common modules or known issues that cause battery drain? Could the Zeder or partially connected multifunction steering wheel realistically cause this? Any typical locations where hidden GPS trackers / aftermarket modules are found? Thanks a lot for any help 🙏 This one is driving me crazy.

Hello everybody i just stoped by to say hello!