Actually, it may not be the brightness file. My problem is when I click on the clock in the blue "button/launch" bar (I don't know the name) my T3 freezes. I need to soft reset it to get it working but it continues anytime I tap the clock.
I think PowerOn is the culprit. It provides configuration of the brightness level, dimming effect, and shutting down the screen.
I used UninstallManager to remove PowerOn, and delete all the deletable a68k files
So I'd like to try to delete any preference files associated with that part of the launch bar. Otherwise, I'll have to do a Hard reset.