what world cause my radio not to work and the onstar will not go off on 2002 Cadillac Seville STS

My radio will not come on and the onstar will not go off and my battery is dead every morning

Asked by for the 2002 Cadillac Seville STS
OnStar is still active. Can you pull the fuse? Check fuse block to make sure there is no corrosion before taking it to a shop for electrical diagnostics. Try Google and search solutions as well. They are a great resource. Good luck