If you've never had the need to turn the instrument lights down, and I've never had to on any of my 240 Bricks, just disconnect the dimmer and solder the two leads together by passing the rheostat ... insulate with a bit of heat shrink or good quality eletrical tape.
The dimmer controled lights, will over time become dimmer and dimmer over time. This fix will keep the instrument lights at their brightest. To get at the dimmer, pull it's control knob and the light switch knob off ... carefully pry the plastic mounting plate off and you will expose the dimmer rheostat. Hope this helps.