Kenmore French door refrigerator won't cool

For my Kenmore refrigerator model number KFIS20XVBL2 but I have also found it as W10740220. The light comes on, the water dispenser works. I have replaced the main control board. I was told by the repairman afterwards that the voltage display board, where the water is dispensed, needs to be repaired. Does anyone know how to repair it?