Anybody mess with one of these? Worked on an excavator today with a non working thumb. Found some shorted wires and had to rewire the whole mess. After wiring the machine, I would get a dead short when activating the pilot valve(electric control button). I finally removed the relay on the coil and wired it direct, worked fine. The schematic on the relay shows diodes between line 1 and 2 with a resister. I'm not sure why the relay is even needed. My fix is a bit hillbilly, but in the bush we do what we have to.
I'm sure HKX in Washington State will help you diagnois.
I don't know about the resister but the diode is there to protect the machine computer. Did you check to see if the diode was blown? They will short through and blow fuses on you.