I have a 2000 blazer with a stock cd deck . I replaced it with a sony cd then switched back now the stock radio will not light up other than the display. None of the buttons light up anymore . No blown fuses or other problems ... Could i have blown the bulbs across the front? ( side note ) ... This deck worked last in my dads 2002 silverado .. Other than the mounting plates i had to change out .
But all in all it works great with the ipod plug in adapter and the sub output i ordered it balances the bass better than the sony .

 

Did the aftermarket have all its lights on before you swapped it? If the lights worked when u pulled it out of the 02 silverado then the bulbs did most likely blow since you say no fuses were blown.

 

did you connect the illumination wire?