So I was reading here that people have had issues with there button not working. I'm guessing it's after the door motor change. If so, do the following.
1. Unplug the motor
2. Move heat and AC controls to heat &vent
3. Move back to AC and make sure the light is on if door is open. (Open means outside is closed off)
4. Plug back in, test button for recirculation. If still not working remove the motor and and plug repeat sets. Then re-install.