Take a volt meter and check if there is 12 volts on the cables on the passenger side compartment. If there is then connect the positive battery terminal to the +12v cable and the negative battery terminal to the -12v cable.
If there is no 12v then sorry, can't help any further.
2007 Surveyor SV230 - 200 Watts Solar/MPPT Controller - 230 AH Battery Bank - 600 watt PSW Inverter - (2) 2000 watt Inverter Generators - LED Lighting - Boon Docking 99% of the time.
2009 F150 - 5.4 Litre - 6 speed - Tow Package