EQC Mirror Heating Failure

That's a bummer. I had a similar issue with my old Volvo C30, although the symptoms were slightly different. My car mirror heating would only work intermittently. The root cause was corrosion in the connector that fed power to the rearview mirror heating element. Check the plug; it might be loose or corroded, preventing proper power delivery. Use contact cleaner to clean it. If the connector looks fine, you'll need to trace the wiring back. I used a multimeter to check for continuity. Do you have access to the wiring diagram for the EQC? That would make diagnosis significantly easier.

Thanks for the Volvo anecdote. Corrosion is always a suspect. Where exactly was the connector located on your C30? Was it within the car mirror housing itself or further upstream near the door harness? I need to figure out where to start poking around on this EQC before I dismantle half the car.

On the C30, the connector was inside the car mirror housing. I had to carefully pry off the car mirror glass to access it. But before you do that, check the door harness where it enters the door from the body. That's a common place for wires to break, especially with repeated opening and closing of the door. Since you have an error code pointing to the circuit, I'd say you should take it to the workshop. 95€ is not much for a diagnostic. They can pinpoint exactly where the break is.

Appreciate the advice! You were right, a broken wire in the door harness. Shop found it quickly. 95€ well spent to restore rearview mirror temperature control and vehicle safety. Thanks again!