Not sure if this helps but the Dump Truck has a hydrolic pump similar to an AC pump, the electronic clutch clicks on/off just like the AC compressor and has a diode between two wires, been a while, I know the diode is directional and the reason it was added was because they found the clutch on the pump would engage intermittently and a engine driven hydraulic pump should not be engaged above 1500 RPMs.
You may get some info on how to hook it up from looking at hydraulic clutch pump wiring diagram.