I am not a professional, I am a homeowner. So I will describe my issue in homeowner terms. A friend gave me his 12 year old refrigerator. I attached the water line to the ice maker and it isn't producing any ice. So I asked him about it and he said he never hooked up the ice maker. Here is what I have observed. The water is getting to the filter inside the refrigerator and if I remove the hose that comes out of the filter and goes to the input side of the assembly in the back of the unit there is water present, but when I remove the green hose that goes from the output side to the ice maker there is no water present. Any ideas what the problem is? Does it use a relay to open a valve to send the water up to the ice maker or is there a pump that pushes it up that green hose? I believe my friend when he says he never used the ice maker because the filter looks brand new.