Hi can anyone help. I have a 07 L200 elegance with the sat nav screen. The dial on the left when pushed should turn on the rear and mirror de mister but for some reason it's not working. The light comes on and also the icon on the screen, I've checked the fuse and seems fine but I was wondering if there a timed relay hidden away somewhere that is faulty? Ant ideas as now winter is getting near it would be good to have them working. Thanks for any advice