Low-signal KTHI was the ABC affiliate, but ABC was doing so well, NBC affiliate WDAZ (Grand Forks)/WDAY (Fargo) enticed ABC with their more powerful signal. Then NBC went to KTHI and also went from the bottom of the pack in ratings to the top with Cheers and Cosby, etc.
KXJB stayed CBS the whole time.
WDIV was when Winnipeg was getting the Detroit signal and subsequently discovered drive-by shootings.