You have to remove the instrument pod to get to the adjustment for the instrument lights.

Once you do you will find on the back side of the instrument panel a white ceramic thing that will line up with the instrument light adjustment dial. This has failed. It is a very common thing that can either be fixed easily or not at all.

I usually spray the insides of the thing with some contact cleaner from Radio Shack and turn the knob back and forth a few times to clean up the contacts. If that does not work then all I know to do is replace it.

They are quite expensive for what you get; around $100 or so. But there are always a few for sale on Ebay or you can post an ad in the 'wanted' section of this forum.

Of course if you buy a new one you will be fixed up for the next 30 years.

Pulling the instrument cluster is easy after you have done it a time or two. Look around on-line for instructions on how to do this as it is different from pulling the instruments on any other car.