Heater not blowing hot air

I have the SUV listed above Eddie Baur Edition. I have replaced both front and back heater cores, I replaced the upper and lower intake manifold gaskets, all blend doors, the blend door actuators, the thermostat, water pump, flushed the whole engine coolant system and replaced with all new fresh coolant and I still am not getting any heat it only blows warm at room temperature and that's all. Both inlet and outlet lines on both heater cores are really hot. The coolant temperature is at 210 degrees. I am at a loss and not sure what else there is that could be the issue. All the parts I replaced I was told by the Ford shop where I live to check and replace. Where should I go from here? Any ideas?