You most likely have a broken wire on the harness from the tray to the machine. Turn the machine off, pull the shelf out part way, unplug the harness from the machine. Remove the shelf (I can skip this step), and check the wires that go into the back of the harness. You'll have to remove the 'cover" over the wires. Most likely, One of the wires is broken in there. remove the bit of broken wire with needle nose pliers and reinsert the loose wire into the harness with a thin screwdriver. Put the cover back on the harness and reinstall the shelf. Your "make another selection" problem is now solved.