If you have air flow at dash but none for floor or windshield; check the vacuum lines. The damper mechanism is controlled through vacuum and a loose or broken line will cause the system to fail. If you have no air flow at all then check the fuse for the dash air conditioner and for power to motor. If you have power feeding motor but it does not tun then the motor is bad. Good luck and keep us posted.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7