Parents bought 2008 bighorn 3670RL and Seller kept battery.

[TeacherSupreme]

Searched, no help. 4 cables red/black together and red/white together. How to connect?

 

[Roller4tan]

Red Positive/ White to ground. Red from 12v breaker row/ WHITE attached to frame ground. Follow the other red and black wires to see where they come from. Black is an automotive ground, white is usually used in rv's for ground.