I found a rebuilder for much cheaper than others, they seem to have good reviews. SDI in Illinois. I plan to use them.
Hopefully what they find inside the box will help me out on a root cause.
My current best guess is that putting full voltage and power to it opened something up inside that had been marginal at best on 10-12.0v with no amps behind it. I don't currently know.
The melted wires are power supply wires to things it needs to go, so no.
Air system checks out reasonable, sounds like a small leak behind the tractor control valve ( I didn't remove that section of dash to look, could also be HVAC control) and I found a couple dried out o-rings on push connects that I think feed the tank pressure gauges. suspension aired up with no leaks. air brakes released and truck rolled a hair even it its parking divots. service brakes apply with no leaks. cab latches removed from the cab to repair hydraulics at home to fully repair that system. rotted exhaust parts removed to duplicate or buy new old stock.
paper work done today, it's mine.
Hopefully I return to it with plates and a computer and drive away (along with some rotten fuel hard lines, setting tire pressures and replacing a couple bulbs). timeline TBD.
