Battery light is on but no fault code

Battery light has been on constantly for the past 3 months, and the rear window defogger isn’t working. However, all other functions of the vehicle are working normally. I left the car parked for 8 days without starting it, and the engine started smoothly, so I don’t think the battery is bad. I also measured the voltage while the engine is running — the alternator is charging properly.

I’ve checked every fuse I could find: under the steering wheel, the 4 fuses on the passenger side, and the main fuse box under the hood. All fuses look fine and intact.

Any idea what could be causing this? I will sell the car but it scares buyers.

https://preview.redd.it/oviacdrccvte1.png?width=2048&format=png&auto=webp&s=b50802ea15892bdd8fb86412d144596f0dc6beba