2003 ls 430.....panel on top of Nav screen showing time and temps takes about twenty seconds to come on and then occasionally flickers....battery was tested three times all good....sometimes all lights go out but controls, ac, radio, etc still work. Any ideas why that bar of lights doesn't work sometimes?

 

Check fuse for that circuit ... consult owner's manual for fuse location.

 

Sounds like an intermittent short. These are the worst to diagnose until they actually fail.