I'm hooking up a brake controller on my 1997 F-350, and I'm having trouble figuring out the wiring under the hood. I have the square grey connector at the rear of the truck (blue, orange, and blk/grn wires) but when I traced it to the front, it's not connected to anything under the hood. It has another square grey connector with a cap on it next to the fuse box under the hood. Coming out of the fuse box is another square grey connector, but they are both male and will not connect. Is there a piece that goes between them? I've been looking over the wiring diagrams, but can't find anything that calls this out.

I bought the truck used about 5 years ago and the previous owner used it to plow snow and had a salt spreader in the back and safety lights on top. He cut off the 4 pronged flat trailer connector before he sold it, but I replaced that a few years back. He has wires going all over the place, so not sure if he's modified this somehow or what? The brake controller connection under the dash works fine and lights up when I step on the breaks, so I'm kinda lost at what I'm missing.

thanks