I have a 2013 Kia Sorento LX and for the past 2 winters the Stereo system stops working. It works fine in the summer, but as soon as the temperature starts to drop it starts to cut out intermittently. Everything else works except for the bottom of the console where the usb plug-in is. That part also loses power. I’m told I need a new stereo. Not convinced it’s not just a power issue but can’t find anything obvious.
Whoever told you that you need a new stereo was likely correct.
The trouble could very well be due to a faulty power issue. You are going to have see if the trouble is located before the connection to the radio or the problem is inside it.
Check your owners manual to see if it has fuse box diagrams. If not, then remove your fuse box covers and see if there is a fuse layout on the inside of the cover. You will probably have at least two fuse boxes, one under the hood and one under the dash somewhere.
What you are looking for is the radio fuse. It may have a manufacturing defect that resulted in a crack. When it gets cold, the metal shrinks and the crack opens up. Not quite the same as a blown fuse and the crack us usually at one end of the fuse where you can’t see it. Just replace the fuse.