The only thing left would be in the dispenser assembly. The water line is clear. The m.pcb is new. The water valve is good and the water line is clear. There is a micro switch that the water dispenser actuator engages which tells the display PCB to open the water valve. If the micro switch reads continuity when clicked that leaves the display PCB and wiring to ne at fault. Since you have the service manual you can check the wiring from the door for voltage to the m.pcb connector for the water valve. Make sure the actuator is clicking the micro switch then take it from there.
I need to clarify a bit. I'm afraid it was late and I had just returned from a night of "playing pool". The m.pcb does not turn on the water valve. The water valve, auger, heaters and crush / cube ice solenoid realys are all on the dispenser pcb in the display assmy. Since this is a dedicated actuator model the microswitch simply inputs to the display
pcb that you want water dispensed. If the water actuator microswitch points are not making contact the dispenser pcb will not know that you want water. If it is making contact the fault would have to lie in the wiring, dispenser or display pcb. There are two pcb's in the display assmy. A dispenser pcb and a display pcb. The water microswitch inputs to the display pcb which then tells the relay on the dispenser pcb to engage. If the micro switch is good the water valve output voltage wire at the connector on the dispenser pcb should be checked. If 115 volts are read the problem is in the wiring in the door, cabinet or harness at the valve. If no voltage is present either of the pcb's are bad. But since they are not sold without the entire display assmy it does not matter which one. Look on page 18 of the serv manual to identify the connector position you need to read voltage at. If there are any noise filter capacitors ( blue rectangular plastic boxes ) in line with the water valve harness that plugs into the cabinet and the water valve they would be suspect as well ( however this model does not show it using those filters ). I hope I got all that right. Still a little fuzzy from last night. Good luck.