[RaptorJB]

Its not the SUN, sure shade will help.... We had the same problem on our 2017 425TS, make sure the door flap that is attached to the left door closes flat, not at an angle. Check door seals as well with a dollar bill after closing the doors, should be tight to pull out. Check the wires on the thermister to make sure they are attached, mine de-attached just touching it. After that our fridge was too cold and had to be turned down to setting "5" not to freeze the milk.... Hope this helps!