Seat Ibiza rear window heating malfunction

I experienced a similar heating issue with my Seat Ibiza. Have you noticed any other electrical anomalies, such as the car struggling to start, or interior lights dimming? A weak battery can definitely manifest in unpredictable ways. In my case, it presented with intermittent rear window heater operation and eventually affected other systems. Please confirm if you observe similar behaviour.

That's insightful. I have noticed the engine turning over a bit slower than usual lately. Did your diagnostic scan also point to a discharged battery, or did you troubleshoot other components initially?

Yes, my diagnostic scan initially revealed multiple low voltage errors across various modules. We initially suspected a faulty heating element or wiring issue with the rear window, but further investigation indicated that a failing battery was causing the erratic behaviour. I would advise having your battery tested and replaced if necessary. It is very likely causing your thermal window issue and general car defrost problems. A workshop visit might be beneficial.

I appreciate the confirmation. I took the Seat Ibiza to the workshop. As suspected, the battery was heavily discharged and defective, impacting the rear window heating. Repair cost was 290€. Thanks for your help.