Go to R.R. jack and unplug the motor from the harness. Use 12 volt power to operate the motor and jack manually in both directions. This will reveal if you have a motor or jack mechanism issue. If it checks ok, run all of the legs down manually by this method at least 4" and do a reset; see manual for procedure. Once retracted, I would recommend you do a new zero point reset as well. Keep us posted on the results.
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