I have a 1995 legacy. I put a kenwood KDC X-996 stereo into my car. All the stereo and speakers work good but the dashboard lights unfortunately do not. I have two illumination wires., one positive and one negative, coming out from my car (the negative is dimmer). Yet the stereo harness only has one wire for illumination control coming of it. Which wire do I connect the stereo to? The positive or negative?