I've checked the fuse, and it is full functional. Its in a 5thGen Civic, and the Stereo fuse, is for both the cigarette lighter and the stereo.. And the lighter works! So why doesnt the stereo work? Its maybe the harness? I have to check one more time...?

 

aftermarket decks usually have a fuse either in the back of the deck, or in the deck harness... check those... it may also be a lose connection... make sure everything is tight.