So even without the gauge cluster in.. the rest of the dash lights still won't work? I mean, it's hard to tell since I have everything out. But I have my clock, and my head unit in. Turn the car on -- the clock goes on, turn the lights on, clock goes out -- display for the head unit dims (note, it's an aftermarket head unit)

And how hard is that dimmer control to change if that is actually the problem? Easier to get an entirely new cluster?