RV Repair: wiring for Jayco Eagle, propane furnace, jayco eagle

Question
We recently purchased a 2001 Jayco Eagle Pop up camper.  The previous owner had the wiring from the battery removed and had the wiring redone just to get the trailer lights working for travel.  We have power only when we plug in to an outside electrical box. The furnace also won't work.  How do we rewire the trailer so we can use the battery power and hopefully the propane furnace?

Answer
what he disconnected is probably the charging wire for the battery.  You will need to run a hot wire from your truck battery back to the hitch area.  You can use the same ground as the lights use.  You will want to hook up a 7 way plug too.  I dont know if you have brakes or not.  Just leave that wire off if you don't.  I am thinking you have a square plug on the frame of the trailer near the tongue jack.  That is the connection for the lights and the other end can be a flat 4 or 7 way.  This allows you to switch the type of connection you camper uses depending on the tow vehicle.  If you have this system, you have separate wires for the lights on each side.  You may also have back up lights capability.  You will need a schematic to wire all these.  get it on line by googleing for it, or google images.  google: pop up wiring jayco 7 way or flat 4.