Need help with stereo wiring problem- 81 300D

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I'm finally installing the JVC KDS-680 in my wife's car, and i'm having a little problem with what is what. I have the diagram from the stereo, and some "help instructions" from an earlier post by ps2cho on 11-25-09, but his was an 87. The car has a Red(coming from a black\yellow wire at the cigar lighter wire) which I'm assuming is the ignition hot; Brown, which was connected on the rear of the Becker (ground); solid Blue, which at first I thought was the antenna, but i'm now beginning to think it was hooked up to a hot wire before; and a Blue with red stripe that's sheathed with black and has a female blade connector. (picture below). On the radio, there's Black(ground); Yellow(battery); Red(ignition-hot); and Blue\white(antenna). Can anybody help me with this wiring? I'm trying to get it done as we speak. Thanks for any and all help. Lee