unless like said above the cable is kinked, reach in the pass side floor board under the center of the dash and make sure there is nto anything blocking the flap from moveing and also check to see if maybe a wire harnes shifted and is on the cable or the flap thoes are 3 things that I have found in some of the 4th gens that we have fixed and also if your A/C blower isn't blowing correctly check to make sure something like a napkin didnt get sucked into the blower box.

Good luck