Lower Ice Maker Not Working

Our Samsung refrigerator has two ice makers, on inside the left refrigerator door that dispensed through the door and a second in the lower freezer drawer.

The ice maker in the refrigerator is working fine, as is the water dispenser in the door. However, the lower ice maker has not produced any ice for over 24 hours. I removed the ice maker and checked the fill tube. No ice at all. The freezer tray on the maker did have some ice in it when I took it out, but was far from full. Before I took the ice maker out, I pressed the reset button for at least 8 seconds as recommended. No noise or movement was noted.

Since there are two Ice makers, there must be a double dispenser solenoid that feeds the ice makers. Before I order a new ice maker, how do I test the solenoid to see if it is dispensing water? Also, is there anything on the ice maker I should check as well?

RFG296HDRS Samsung French Door Fridge
Our lower ice maker is freezing up. We have defrosted 3 times and then the ice maker will work but after a couple days it is not. It acts like it is dumping ice, but the water line into the ice maker gets frozen. Any suggestions?