Boxer rear window heating problem

Interesting. I had similar rear defroster issues on my 2018 Volvo V90. Error codes, weak windshield heating... Sounds familiar. What voltage is your battery showing when the engine is off?

Thanks. I haven't measured the voltage directly, but the internal system shows a big drop under load when the rear window heating is on. Did your Volvo do the same?

Yep, exact same thing. Voltage would plummet when I hit the rear window demister. Ended up being a bad cell in the battery. I'd get it checked out at a workshop. Saved me a lot of headache.

Thanks. Based on that, I'll get the battery checked at a workshop. I think it'll need replacing, costing around 290€. Your help is appreciated.