Frigidaire Refrigerator Ice Maker and Water Dispenser not working

I have a Frigidaire side by side refrigerator model GLRS267ZCB3; the ice maker and in door water dispenser have been working erratically. I replaced the water filter, and at first it seemed to help, but the icemaker is not producing ice and the water dispenser only spits out a few drops when actuated.

I have water going into the 3 way valve, but nothing coming out to the filter supply line. The solenoid coil shows ohms resistance, but I only see a couple of volts on the connector. What powers valve one, which seems to supply water to the filter so it can in turn supply the icemaker and in-door dispenser? Should it always be powered up (assuming power is on and doors closed)?