Samsung refrigerator dispenser controls not working

Samsung refrigerator dispenser controls not working, all buttons not working. Display has the 3rd led from bottom in freezer section lit. Is it the errror code for bad freezer defrost sensor? Tried to check ohm reading for sensor at pcb, had open circuit. Wire colors did not match tech sheet. CN40-6 was blue not blue/grey.
I have very little experience with Samsung, but does this look like the defrost sensor needs to be replaced? I don’t see any listing of a “defrost sensor” in the Sears parts listing. I see Refrigerator sensor, thermal fuse, fixer fuse, fixer sensor. Which one needs to be replaced?