It's a solid blue color. There should be one coming off of your deck. It's easy. And one more thing that a lot of people forget to do, i reccommend running your power down one end of you car and the signal cable down the other. It's the best way to prevent noise such as alternator whine and such later on in the future.
Well said, I have power lines on the left side, others on the right. Remember to keep ground wires as short as possible and power lines from the battery fused!