All buttons are back-lit, but the screen is black and nothing works. Unhooked battery and let it reset, but nothing....any suggestions????

 

Either will work. They are turn on wires. Installed and aftermarket radio. Used blue wire for amp turn on. Blue white was taped. Recently installed a powered under seat sub and used the unused blue/white for sub turn on. Either one just lets whatever know the radio is on and wakes the amp. They are basically interchangeable.