Hi @monk58419,
Have you verified that the temp is correct by placing a suitable thermometer inside the freezer compartment?
Just asking because ice only begins to form at 32°F and the temp you say is 40°F, presumably shown from the control panel.
Also is the evaporator fan inside the freezer compartment operating? You may have to listen for it because it will stop when a door is opened and start again when the door is closed. It will be operating as long as the compressor is operating.
Have you visually inspected the mainboard to check if there is any obvious problems on the board e.g. heat stressed or burnt out components?
Don't know about now but in the past GE used to place the mini manual (service data sheet) in their appliances either behind the kickplate (if the appliance had one) or in the back somewhere. Maybe worth a look as they have the diagnostic test procedures etc.
The mini manual part number is 31-51525 but i can't find a free download online. You may have better luck.