At first I thought the radio digital frequency display digits were completely out, but today with the sun shining on the display, I could actually see that the display is working, but is VERY dim. I can shine a flashlight on the display to see the digits as well. All of the rest of the radio control backlighting works fine, and the brightness levels are controlled by the dash lights dimmer control.
Is there possibly a separate wire that controls the brightness level of the digital display that may have come adrift? Somewhere in the car's past someone appears to have screwed around with the interior lighting, as the wiring to the overhead reading lamps are disconnected at the bulb fixtures, and the bulbs and lenses for the lights above the rear doors were removed (found them in an envelope in the glove box}. I'm thinking the car might have had (and may still have) a problem with those lights staying on all the time. I also found documentation for some sort of aftermarket remote doorlock and security alarm system that may have been poorly installed that might be part of the problem.
While I am on the radio subject, how do you deal with the factory radio antitheft security code issue? I have no idea what the code might be. OTOH, after I had to replace the car battery, the radio worked fine, so maybe its already been hacked around? On another of our cars , some previous owner had fortunately put the code on the case of the radio. Can I get the code from a dealer through the VIN number?