[D-A]

Sorry for the reply delay. I was trying to use the pic with art and had to paste in word. To large to attach then.

Yes the plug is the cart recepticle.
The white wire in it is on the neg side. It goes to the solenoid on the right in the picture. From there a 6 ga blk wire goes to the positive post on a battery.
The black wire in the cart plug goes to the top of the black box like thing (controller?) second from right in picture. From there a 6 ga black wire goes to the neg battery post.

Hope this helps clarify