gauge cluster grounds

1997 c1500 truck, my gauges are acting up when i turn my headlights on, i assume this is a ground. they seem to work but when i turn on my headlights they all max out, the headlights work fine though as do all of my lights, brakes, turn sigs. also my high beam indicator is backwards, it comes on lowbeam and on highbeam its off, also my turn signal indicators are on all the time when i turn the lights on.

i looked over all the connectors i've pulled and i dont see any missing grounds but it has to be something i removed from the old engine thats screwing it up.

the only place i've looked is the C100 connector that plugs into the firewall since that where a majority of the wires came from, but i dont see any grounds on it