Terry for Model Number GDF620HSJ4SS Dishwasher totally inoperative, no lights on display. Unplugged, door carefully/fully closed and it lit up. Thought defective tub side door latch switch so I changed that and unit worked for about a week. Then totally inoperative again. No lights at all. Confirmed power to the unit at the receptacle. Question: is this a symptom of a defective control board, defective UI board, or both? Anyway to diagnose further? Which part would you replace first based upon these conditions? Thank-You very much
Answer Terry, the machine control WD21X24900C would need to be tested at the 5 wire connection J722 from the black/green wire at pin 2 to the yellow/blue wire at pin 5 for DC Voltage. If there is not 13.5VDC when power is applied to the dishwasher, the machine control has failed and would need to be replaced. If there is 13.5VDC, the user interface control WD21X31902C would be the most likely failure. Read More... Answered by AppliancePartsPros.com | Tuesday, October 26, 2021