Did you ever figure the problem out? My radio lights won’t turn off and I’m trying to figure out what’s going on. It’s killing my battery

 

Are only radio lights on or are all other lights (other buttons, tail lights, side markers) stuck on as well?

 

it’s literally just the radio lights. The volume and tuner knob aren’t on, it’s just the inner part of the radio.

 

This all started just after I installed a diode dynamics hyper flash relay and some switchbacks. I went back to the stock bulbs and stock relay but no luck ☹️

 

Radio illumination in this car is weird. Whole car is pretty much wired through one relay (namely, tail light relay). Side markers, tail lights, license plate, and all of the interior lights, except the radio, are pretty much connected together. That's why everything illuminates when you use the remote and outside lights flash.

The radio however gets the same signal as all other lights, but it doesn't drive the front panel lights directly. Instead it uses some circuitry to analyze how bright those front panel lights should be, and then it adjusts them accordingly.

Because it is separate, there is an additional chance of failure. There are couple people on the forum complaining that only the radio lights are completely dead and my bet is on that internal light driver as well. It is about the same with you.

If you feel like taking dash apart and checking some wires to be 100% sure that radio is at fault let me know and I will write which wires to check. You will need a multimeter.

So now when you are tired of my explanation, let me write that pretty much only way to fix it is to replace the radio. (of course for a 100% diagnosis you would need to perform couple tests)

Alternative would be cutting power to illumination circuit of the radio (it might work, no idea tho) with obvious drawback of not having any lights on radio panel. If cutting wires going to illumination circuit would work then you might be able to bypass that circuit but that would require taking radio apart. Then you would need to test if parasitic draw went away.
Also I don't really know where radio gets the power to drive those lights. If it uses its main (always on) supply then you are out of luck on that idea.

You might try to disconnect the battery for couple minutes. I don't think that circuit has an ability to reset (since I doubt it uses a micro controller of some sorts) but that would not hurt anything.