I am having the same exact problem as you, the thing worked in January for the seatrail so I believe the unit is probably ok but who knows. I have undone all connections, lubed everything with wd-40 and insures the connections were tight. I've replicated the problem sitting at dock connected to shore power, while motoring, and on batteries. Will go over connections once again and clean spade connections with with a chemical cleaner. Keeping my fingers crossed..