Explorer Rearview Mirror Heating Failure

Interesting. I had a similar problem with my old 2014 Audi A4. The mirror heating stopped, and it turned out to be a corroded connector. Did you check the voltage at the mirror connector? You’ll need a multimeter and some basic wiring knowledge.

That's a helpful pointer. I will test the voltage at the mirror connector. If the voltage is fine, does that eliminate the connector as the issue? Or could there still be internal corrosion affecting the connection even with voltage present?

Well, in my case, the voltage was completely absent, so it was pretty clear-cut. However, just because you're getting voltage doesn't mean the connection is 100% solid. There could still be internal corrosion creating resistance and preventing the heater element from working properly. If you're unsure, and especially because there is also an error code, I would advise getting it checked by a professional. Mirror replacement can be surprisingly tedious.

Appreciate the confirmation. I had been hoping to avoid a trip to the workshop, but I concede that this seems the prudent course of action. As I suspected – bad cable or plug connection – the bill amounted to 95€. At least it wasn't worse!