I have a GE Monogram model ZISB420DMD fridge. The ice maker has stopped working. I have replaced both the ice maker and the water valve assembly. It is not filling up with water, and therefore not making ice. The fill tube is clear. I know this because I can switch the leads on the valve and fill the ice maker manually by pushing the water dispenser in the door. Is there some circuit board that controls this function that is not onboard the ice maker? Any other suggestions?

Thanks
David