Kitchen Aid undercounter ice maker over producing ice

[Larry the applia]

Model KUIC18NNZS Original problem no water after customer done a clean cycle. Replaced valve. Customer called unit wont stop producing ice. Went back out checked bin thermistor in ice bath seems  to be in spec. Placed sensor lower in the bin to test still over producing. I had similar unit before doing same thing. Another service person replaced bin thermistor problem was still there. I went on unit replaced control board and unit still over produced. They replaced unit so never fixed that unit. I know I am overlooking something hope someone else has had this problem