Tractor Repair: Case MX120 dash not working., negative battery cable, case mx

Question
I have a case mx 120 (year 1998) the digital display and digital hour clock wont work. I have tried a new dash console and it did not cure it. I have checked the wiring and fuses and cant find anything wrong. The lights on the top display work and the fuel gauge lights up. Any ideas would be greatly appreciated.

Answer
 Check the clean ground wire to the negative battery cable clamp.  Remove the battery box cover, and there should be about 3 ground wires attached to the clamp bolt on one of the negative battery cables.  The instrument cluster gets its ground (earth) directly from the battery which is called a "clean ground."  I have seen these wires broken, corroded, or hanging loose and not connected.