have problem with ice-maker in my amana model SZD26VFW,Ser#0001250426?

Does someone know how the ice cube tray signals the valve to shut off when the tray is full of water? and what is the correct positioning of the water fill tube to the ice tray?
I have tested the shut-off valve by lifting the lever so that ice cube production is stopped. There is no water dripping indicating that the valve is o.k. When we move the lever to make ice cubes, the water drips from directly below the water tube and runs into the ice storage bin.
I believe that I have a problem with either : (1) The water tube is not correctly positioned to fill the ice tray and there is some over-flow or (2) Whatever is supposed to signal the valve that the ice cube tray is full is not doing its job.
The manual received with the ref/freezer has no information on correct placement of the water tube or how the valve is signalled to shut off.
I also tried moving the fill tube and one time must have pinched it shut. As a result, it filled with water and froze. I took the frozen tube out of the freezer and thawed it out. When i put it back in the dripping when the tray was filling started again.
One of the advertisers of repair parts made mention of "wicking" with the solution being to replace the ice maker. Anyone have any experience with that?