I also use the US GEAR system. My only problem has been with the umbilical cord connections needing lubrication and tightening about 3 times a year.
In addition to the ground, low or high voltage could cook your solid state board. Maybe finding another power source might help. Because it fails after one year, it may be the power source is zapping the control unit and after so many zaps, it fails.
When it fails, it the symptom that you have no "march of the red lights" when starting the coach? How do you know the system has failed?
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
The Avatar Is Many Times Around The USA
Nobody Knows Your Coach Like Somebody Who Owns One Just Like Yours