2000 vnl 64 660 with d12 cab elect. issues

just joined the forum and i know how people can be on these things........... I just bought a 2000 vnl64 660 i think lol i am having issues with the truck gauge cluster not powering up and no dash fan and no wipers there could be other things not working but have not gone any farther testing what works and what does not. when the key is turned on most of the time the items menctioned wont work but the odd time they will. if they dont work i test for power at the fuses and no power is found. i have cleaned the ground cable at the batterys and the ground post at the starter and the ground post on the block below the starter and the ground wire in the left front wheel well. starting to lose sanity if the truck is running long enought some times it lights up by its self. with as many things dead thinking there is a contruler or something not powering them up? have no information on this truck and some where to start would be nice. I have been reading and sounds like the dash in my truck might be digital so maybe can bus bt i pulled the cluster and did not find any twisted wires so thinking it is not. the truck runs and starts fine even with the dash and acc not working just not sure what to do next thanks

 

I have tryed back feeding the cluster fuse and wiper fuse and and when I do the item I am powering up works. Now what I am trying to figure out is where the cab groung stud is cause when I have played with the main ground wires at the starter and eng block stud some times the acceroies will light up untill I shut the key off and will not turn back on right after when the key is returned to the start position. There has to be corsion some where or a bad ground wire would only explain why things will start working after the groung wire arcs. Where is the ground stud m6.