In my camper, with a WFCO panel, the converter is directly behind the power panel. Take off the cover and pull the screws holding the panel to the wall. Pull it out of the wall. The two heavy gauge red wires in the same bus by the fuses - one goes to the battery and one goes to the converter. Since you have done all this and you have those "red and white leads that go no where," you may not have a converter, as Lou suggested. Yes, it may be as simple as buying a converter and connecting those two wires, then plugging it in.
All converters are not created equal. I am the wrong person to ask which one. You may want to start a new thread for suggestions on which one to get.