Cat 289C Short to ground

Hey guys, long time viewer first time poster here. I've been able to fix a lot of issues on different machines over the years just by reading through existing threads on here, I greatly appreciate it so far, but my current issue has me stumped I have a 2010 289c JMP01342 2900 hrs. I've been dealing with the 20 amp fuse for the key switch located behind the cab by the ecm, blowing and killing the machine instantly. It has happened twice, the first time i just replaced the fuse and it was good to go. about 40 hours of runtime later and it happened again, but the this time it continually blows the new fuse instantly, over and over. I found the yellow wire on the key switch had continuity to ground which i didn't feel was right so I began tracing it via continuity and found it at the connection where the harness goes through a 2" x 2" plug with an 8 mm bolt in the middle of it. There is 2 of these plugs on the right hand side of the machine next to the hyd oil tank. The one with the wire in question is the upper plug, and the specific wire is in the top row of pins in the 7th spot from the right looking at the plug while its plugged in. When I unplug it i lose continuity to ground on the cab side of the plug, but on the engine bay side continuity to ground remains. If i leave this 2x2 plug unplugged, replace the fuse and turn the key to the run position everything is fine, as soon as i plug it back in, the 20 amp key switch fuse blows instantly. Is there any chance some knows what that wire does or has a schematic for this machine. Thank you in advance.