Seems the instrumentation panel illumination on my old 1993 LS400 is
failing - sometimes (not all times), when the car is cool, the illumination
would not be on until after driving 10 minutes or so, then it starts to
flash a few times and then it turns on.

What's causing this and what should I do ? Would I need to change the
whole instrumentation panel or maybe just some lights/switches ?

Thanks for any diagnostics /suggestions.

Joe