From the owner's manual, it's the F9 5amp fuse in the driver side fuse box. It was a little daunting accessing the fuses via the side panel of the dash with the driver's door open. When I got to the fuse, it was very firmly in position - took quite a pull with long-nose pliers to remove it. As I didn't have a replacement to hand, I put the same fuse back in, and the charge port lights have worked ever since! I've attached the owner manual page, I think the fuse board map was orientated differently from memory - you might need to rotate the image - you'll see what I mean when you get in there!
Hope that helps and fixes this glitch for you, Good luck!