I have an 89 LSC and suddenly, like in the last couple of days, when I turn on the headlights the Trip Computer, Compas and Temp diplays all become so dim you can not read them. The Heater/Ac Controls and Radio display also dim, but are still readable.

It only happens when the headlights turn on and the only thing I chaged was to install a replacement electric eye for the headlight dimmer.

Any suggestions as to what would cause this?

Did you adjust your "panel dim".

That'll do it, is your speedo also dim?, if so, just go out and scroll panel dim all the way up, right before it clicks to turn on the interior lights. :zgreenbou