lombo1

My 2010 SEL has an odd A/C issue. After driving for about 2-3 hrs all of the vents will close up and not allow air to blow out. Fan still working and I can feel cold air trying to get out. After I shut the car off and let it set for a couple hours it works fine again. I replaced the 2 blend door and main door motors, still same issue. It affects all dash vents, floor and defrost vents too. Hard to diagnose because it only happens on longer drives. Any advice? Thanks