No gauge cluster lights

2000 silverdo in sig

I have no gauge cluster lights.
All gauges work fine other than lighting up at night.
Radio lights up and works fine
Ac control lights light up fine
dome light works
dimmer switch works
The digital read out in the middle works. Will also dim and brighten when dimmer switch position is moved along with ac and dimmer switch lights.
I check all fuses that would control gauges. good
I also check all fuses suggested through google searches. good
I also literally check every fuse in fuse panel under hood and inside cab on driver side. Good

From what i read online i believe i may have i loose wire in behind the dimmer switch. just assuming. I havn't got that far yet. Just wanted to see if you guys or girls have any suggestion into pointing me in the right direction.

I should also add. they were working at one time. i believe i was missing with the dimmer switch one day during the day and drove truck at night days later and noticed it.

thanks for any tips