No power to display (cluster) monitor

I really need help with this issue. For over a year now we have not had power to the display monitor. Had a mechanic check the wiring and said display was bad, bought a new one and nothing happened. We have checked the prongs on the plug in and a couple have power but it must not be the right ones. Fuses have been checked wiring checked. I did find a basic diagram that showed a prolix resistor switch. Does anyone know if this could be keeping power from the display monitor or from the CPU Controller? Any help is appreciated!! we have been running the machine without display working but throttle control is off and hydraulic pressure is off. If you walk the excavator you have to play with it or it can bogg down. Its a farm use machine now so not used a whole lot.