I have a whirlpool side by side refrigerator, model #GS6SHEXNB. The refrigerator side isn't cooling. The freezer and ice maker work fine. I removed the back panel and have checked and   cleaned the condensor and fan (both work). I can hear the compressor running. I have removed the inside back panel, the freezer fan works, the evaporator coils were not heavily frosted (therefore not a defrost issue). I cycled through a melt/frost and that new frost appears even. I removed the damper in the refrigerator (upper left, connected to thermostat module)and it wasn't obstructed and did operate. I removed the plastic chutes on the freezer side and they aren't obstructed either. I can feel plenty of cold air from the freezer, but just not enough in the refrigerator. There's a vent midway in the refrigerator section (next to vegetable draw), but it has no connection to freezer that I can see. What the heck is left? What could this be?