2005 Gearbox 260FS Battery Issue

Ok just checked out some more stuff... I pulled iff the cover from the converter and was getting 9V when the disconnect was on. Zero volt when off. I then check the voltage behind the disconnect and was getting 12V when off and 9V when on. So I disabled the disconnect and as soon as I connect the wires going from the battery to the converter the voltage drops to 9V. I then go back and think I am having an issue with my battery so I hooked up jumper cables from my truck to the new battery on the trailer. I was then getting 14V at the battery and behind the disconnect. As soon as I make the connection to the converter it drop to 10V and still nothing on the trailer works.