Many systems are maxing out the switch's amperage rating and the switch's do not last very long. Reverse the wiring connections on the switch and if it now extends OK but has a problem retracting; it is the switch.
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