Wiring help?

[jbradley4809]

I have a 2006 Ford f450 converted into a wheellift. This weekend, the boom stopped working totally. Under the hood, the PTO relay (I doubt that's the name of it, but it definitly connects power to the pto and the uplifter switch?) was partially melted. It does not sit near anything that should have caused the damage. Tried to replace the relay and put each wire back the way I removed them, boom still does not work. I have enough knowledge to understand there's a good chance something grounded out to cause the heat initally and there's a problem elsewhere, but I have no clue what i'm looking at under these uplifters and dash. It's really poorly ran and speghetti. 

 

At the relay, I can supply forced power to what I believe is an uplifter switch power wire and get the boom to work. So I know it's definitly something in the wire. Using a test light, I have no power anywhere besides the straight power from battery. However, when I use test light on on power side of battery both wires light up as grounds. Inside at the uplifter switch itself I was able to find which wires are receiving power, and which ones sending power when the switch is turned on. So i want to assume that's the wire that grounded out somewhere, perhaps broken between the switch and the relay under the hood. If I run new wire, i'm concerned that may accidently bypass the wheellift controller. I have NO clue where that goes or where the relay that controls that is. 

 

I know it's a lot, but is anyone able to help me understand this issue better so I can resolve it myself, or atleast point me in a better direction? I can't find diagrams, can't find anything this particular online.