I have a 01 Z71 with stock Delco CD/Stereo. The backlighting on 2 of the buttons have gone out. #3 and #6 are dark. I pulled the faceplate off but it looks like an integrated circuit board behind it. Does anyone know if I can replace the lights or someway to get them to light back up? I sure don't want to replace the unit just to get a couple of lights to work. thanks.