Hit test button on ice maker and cannot get it to start

Hope someone can help me with this icemaker issue iam having at a customer home. Customer’s icemaker was frozen , I defrosted the ice tray and ran the test couldn’t get icemaker to to test ordered new icemaker went back install new icemaker , hit test button again still nothing, except when I unplugged Icemaker quick disconnect plug from from side and plug back in water comes into icemaker. told customer to let it run and see if it would make ice . Customer called back after couple days still no ice, I went with new icemaker checked connection from control board found wire backed out of plug reinsert wire also replaced thermistor inside auger motor housing .I still unable to get unit to harvest. Sorry for the long email hope someone can help me with this one. Thanks guys. ..