I bought a 2019 big horn black edition crew cab a couple months ago. It now has 1500 miles on it and the last few weeks I’ve been noticing a mildew odor. I don’t have the panoramic roof so no leaks there. I have checked all the carpet and headliner and can’t find anything wet. It seems to be happening once the heating system turns on because when I get into the truck in the garage it smells good. Once it runs for a bit is when I’m noticing the odor. Anyone have any ideas what this could be?? I have an appointment at the dealer next week but they had no idea other than to replace the cabin air filter which can’t be bad after 1500 miles.