I can't help with your request for locating and getting service but maybe you can solve this.
I'm fairly certain that the inverter in those RV's needs to be "on" to pass shore power through to the coach. For the inverter to be "on" it needs to "see" a battery so at least one ecotrek module would need to be turned "on". For an ecotrek module to be turned "on" there's a supporting AGM battery that needs to be above a minimum required voltage.
I'd first locate that supporting AGM and charge it.
See this post for info and reset procedures: https://www.classbforum.com/forums/f...tml#post111637