2003 Mack CX 613 intermittent gauges

[Walkyrie_Engineering]

been having a growing problem, our gauges keep dropping in and out. at first it was just the fuel gauge being erratic and the speedometer randomly became slightly causing cruise control to kick off, now the entire panel comes and goes, and the seatbelt warning is coming on now. i replaced the entire dash cluster assembly, unplugged the ecu harness and cleaned them as well as some various other plugs i came across. the only thing that seems to have any effect is if I jiggle the bundle of wires coming out of the firewall in the engine bay that run under the truck. if anyone has any suggestions that could help me narrow down the culpret it would greatly be appriciated.

[Walkyrie_Engineering]

I believe I have managed to solve 80% of the issue, turns out my cluster gets it's ground and power from my starter. the contacts were a little corroded I pulled them and cleaned them and they haven't seemed to cut out since so to say. except for the fuel gauge and speedometer going slightly off every now and then, I imagine its a bad ground or power wire on them as well but still having problems on tracing down where they ground out and get power. if anyone has any suggestions I'm happy to hear them.