4Runner rear window heating issue

I had a similar issue with my Toyota 4Runner. The rear defroster and windshield heating are often linked. If the error memory mentions low voltage, a failing battery could definitely be the reason. Have you checked the battery's voltage output? What does the error code say exactly?

Thanks for the quick reply! I haven't checked the voltage output directly, but the error code is fairly generic, something along the lines of 'rear window heating circuit malfunction'. It just seems odd that a battery issue could cause such a specific problem. Is it common for these systems to be that sensitive to voltage fluctuations?

Yes, these systems are often more sensitive than you might think. The rear defroster draws a significant amount of power, and if the battery isn't providing enough, it can trigger errors and prevent proper function. Given the vague error code and the windshield heating issue, I'd strongly suggest having a workshop properly diagnose the battery and charging system. It's the most likely culprit.

Okay, thanks for the advice. I'll take it to a workshop and have them check the battery and charging system. Hopefully, that will resolve the heating issue. I'll post what I find out.