Hope someone can help !! I have a "FOG" on the inside of my window. It comes when I drive for more than a few mins. It doesnt matter what I turn the fan on or how hot. It does not clear off. i have a new 2018 murano. Took it into dealer, it is not a heater core issue ( they say) and it doesnt seem like a film. But very annoying driving into the sun or at night. I have to stop to wipe the inside of the window. Any suggestions ??