I've been testing my Multiplus 3000-120-12v in my Grand Design Imagine travel trailer. So far, I have only tested Output 1, since I am not connected to shore power. I have the chassis ground connection of the Multiplus grounded to the trailer chassis. The incoming shore power ground is connected to the Input Ground on the Multiplus, but I understand it is not used unless power is detected. The Multiplus Output ground goes to both load centers: (1) main and (2) shore power only. I was advised by the Grand Design technical support that the existing bare wire going to the main load center's ground bus is connected to chassis ground, so I disconnected that wire in favor of the ground coming from the Multiplus. I have tested Output 1 and I am able to run the microwave, TV, etc. from the batteries. Unfortunately, the GFCI receptacle is tripped and can't be reset. Any ideas to get the GFCI problem fixed?