The piece that has fallen off the controller is the auto reset circuit breaker. Someone needs to check the voltage at the motor under a load. I bet it is breaking down. I would not be surprised that it is at the controller. The circuit breaker should not fall out. This means that the connections are loose. Also check for good grounds.
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