Tony, if you have four cables two are probably to chassis ground and the other two would be B+. Ohm out the cables and the chassis cables will have 0 ohms of resistance to the chassis. The other two would have a higher resistance and these would be connected to the 12 volt + post of the battery bank.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 350 ISC w/ Banks = 450Hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7