You have not solved the problem.
You mention fuses and beaker in your original post. If the trailer has a breaker panel and that breaker was what was blowing I would lift the wire off that breaker and put it on another breaker of the same size, have first removed any wire on that breaker. If the breaker holds your original problem was a weak breaker and it should be replaced. If the second breaker blows also there is additional load on that circuit causing the problem. To check this out you will need a clip-on amp meter.
You mentioned fuses. There should be no fuses on the input side of the converter that would hold and still blow the breaker unless the breaker was weak.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles