Seems to be a knowledgeable group...hopefully I may get some help.
History, LG LFX31945ST compressor running fridge and freezer not cooling. I called LG support indicating that I thought the compressor failed after my research. Fridge out of warranty, compressor warranty. They said they would send a tech out but I would have to pay for labor...okay. Following week tech comes to change compressor but encourages me to also change three way valve. Said he recommended I do as they fail and it would be another seal system cost to do it in the future. I am not a refrigerator tech...but I am a technician otherwise. He changed compressor and valve, told me to give it 24hours and left. Next day fridge cold freezer warm. Called them back, they said following week a tech would come and check it. A different tech came. I told him about the valve, which is what I was now suspecting. He said no, it was a blockage and they could not fix it and LG would refund me or give me a replacement...yeh right. After talking with LG, I would get less than two hundred dollars for my more than three thousand $ fridge...as I paid for labor and three way valve.
Still suspecting the valve, I did more research and figured out how it works, also about the home position, test, and feeling for rotation. As an electronic tech I know about stepper motor. So I removed the coil drive and apply a magnet to rotate the rotor. I can now get the freezer and fridge evaporator to frost, the fridge alone or the freezer alone to frost. So I cannot believe it is a blockage. I looked at the part # for the valve installed AJU74892401 more research said the part number should be AJU34510512 which screws on the frame. I do not know what was on it before. I called LG parts and asked about these two parts, after awhile told me either would work. So now I can't claim that it is the wrong part. Any help would be appreciated.