Burnt wire

I'm 99% sure I found the problem, gentleman. I had to dig through some boxes and found an old manual on CD. From what I see that terminal should only have one wire going into it. I chased where that wire goes to and found it basically splits between a ground and the ignition switch in the interior and then under the hood going to the ballast, alternator Etc. So I pulled out that aftermarket air conditioner that I had packed into a box and looked at the wiring on that. The black one in the picture by my thumb came through the firewall at one time and just the last half inch of it is hard as a rock while the rest is pliable. Like I mentioned before I thought it was a horse bleep installation.

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