Megane rear window heating failure

Sounds like a significant voltage drop. Like trying to power a house with an extension cord. Given the error code and dual heating failures, have you tested the battery's state of charge and its ability to hold a load? A discharged or defective battery can cause electrical issues.

Thanks, I appreciate the analogy. I have not load tested the battery, focusing on fuses and connections. Could a failing battery cause only these heating circuit malfunctions while the car otherwise operates normally? I thought other systems would show distress too.

Yes, it's possible. Modern cars prioritize essential functions. Heating circuits are often disabled or underpowered when the battery's capacity diminishes. If you've ruled out simpler causes, and considering the error code and symptoms, I'd advise a workshop perform a battery test and electrical system diagnosis.

I appreciate your insight. It was the battery! After a battery replacement at 290€ the issue is resolved. Thanks again for pointing me in the right direction.