HELP...compressor won't shut off

That's an easy one, Air Governor mounted usually to back side of air compressor needs replaced. In addition since this air compressor ran continuous for so long, have the Desicant spin-on filter replaced which sits atop the air dryer which should be located behind driver side fuel tank inside frame rail. It spins on/off just like an oil filter with an o-ring between the filter and the seat. Total parts cost about $55 - $60 dollars for air governor and desicant filter and both very easy to install. If you are not familiar with air governor pressure adjustment, simply install it and leave that adjustment screw on the end alone. Don't touch it, don't move it. It should be pre-loaded from the manufacturer to operate at about 120-lbs. If it is off by more than 5-lbs in either direction, have a qualified mechanic perform pressure adjustment.
Internationals use Desicant Cartridge number U-55 950011K / 3046408.