I suggest you start with a Volt Ohm meter.
Check each cable, with one goes to chassis ground?
Which one goes to a fuse?
How many batteries?
If 6 Vdc the you have either 4 or 6. That equates to 2 sets or 3 sets in series and then parallel. Next time Photos before you remove. You should post this in the specific group forum on your rig
Dale&Susan, 08 Alfa Gold, DaGirlsRv,
KoKo(Rainbow Bridge)&Della(Rainbow Bridge) 08 Jeep Liberty_Solar_940W Solar_660 AmpHr