newer ge french door ref water line freezing up

Refrigerator & Freezer Repair
1

Found the water line frozen in the upper left door. Applied heat and got the icemaker and dispenser working again. customer had temps turned way down. Now icemaker doesnt work and I found water pooled behind the reservoir and it had dripped out bottom of left door inside fridge. water dispenser still works. Going back with thermistor but has there been issues with this? Havent seen much in my area with these other than the ref section evaporator fan motor. TIA…