Here's the ground I originally found, left side of cluster, above the HVAC controls. Black and gray, banking on CI 34, main harness ground. This is a crank-window Charger, no power features. Then, I found this stud behind and just above the ashtray, with nothing attached to it. Seems kind of strange, since this is functionally the middle of the dash.

The alt gauge appears to now be damaged, it reads between centered and "C" and moves for nothing. Temperature gauge still goes properly maxed out once key-on is applied. Fuel gauge is safe and functional.

And is it just me, or does it look like someone has already been in this wiring? I've never seen that kind of electrical tape in a stock Chrysler product from 1976. That seems...newer.

Tomorrow I will attempt to start the car with no gauge cluster in place in the hopes that I can charge the car where it sits, instead of having to unload my entire garage, shove the car out, and tow it to where my wife's Silverado can get to it.