Rifter rear window heating failure

I had a similar issue with my Rifter. Check the battery's voltage and overall health. In my case, a faulty battery was indeed the culprit causing the thermal window to malfunction. Do you experience any other electrical issues?

Besides the defroster issue, I haven't noticed any other obvious electrical problems, but I will have the battery load tested. Was your windshield heating also affected? Did you get any specific error codes?

Yes, the windshield heating was also underperforming. I didn't write down the error codes. I recommend getting a proper diagnostic scan, but a battery replacement sorted everything out in my case. Given your symptoms and mileage, and to prevent further damage to the electrical system, you should probably take your car to the workshop as soon as possible.

You were spot on! The battery test confirmed it was failing. A new battery fixed the rear and windshield heating. It cost me 290€, which is annoying, but at least it's sorted. Thanks for the advice!