cant take credit
Tools/Equip:
Wire Strippers
Needle Nose Pliers
Sockets
Wire Taps or Crimps
Wire
Aux Audio Cable you are willing to cut
1) The first thing you need to do is remove the radio. A tutorial for this can be found on chevycobaltforum.com
2) Disonect the harnesses attached to the back of the radio. There should be two, or else this tutorial will not work for you. We will be using the smaller of the two. It is a 12 pin connector, with 5 wires going to it. Three of these wires carry the audio from your XM receiver to you Head Unit.
3) The three wires referred to in the above step should come grouped together from factory. In this picture, they are the three wires on the left. Green\White, Brown\White, Tan\White.
4) Depending on how you choose to connect to these wires, the following steps will vary slightly.
5)
If you are using wire taps: Cut three short pieces of wire, make sure they are the same gauge as the harness. Crimp one wire tap onto each one of the wires pointed out earlier, along with one of the pieces of wire you just cut. In the picture below, ignore the two wire taps in the background. You should only have three, which match the three in the foreground.
6) Take your Auxiliary Audio Cable and cut off one end. There Should be three wires. Two should be sheathed, and the other one should be uncovered; this is the ground.
7) On the harness, as mentioned earlier, the three wires we just tapped into carry the audio from your XM receiver to your Head Unit.
Tan\White - Ground
Brown\White - Left (Or Right, does it really matter?)
Green\White - Right (Or Left, does it really matter?)
You will now want to connect the three wires from you Aux cable, to the three wires above, you can see them trailing into the foreground. The ground wire on the Aux cable goes to the ground on the harness. And the other two, go to the Green and Brown wires on the harness.
Use wire crimps to connect the wires on the Aux cable to the corresponding wires coming from the harness.
8) Tune your XM radio to channel 0, and plug in your music player. It should work. If it doesn't, check your crimps and splices. See if your audio changes when you wiggle them. Redo each as necessary.
9) Put everything back, and crank that shit!
Bonus:
After wiring mine this way, I noticed that my audio cut out intermittently because the taps I used were to big. I then decided to use crimps all around instead.
To do this, I cut the three wires on the harness. I used a single crimp on each wire to attach the wire coming from the connector, to two wires. One of these two went to the Aux cable, and the other continued to the factory wiring.
This enabled for a cleaner installation, and most likely a more reliable one
Add Auxiliary Port to 05-07 Balts 
Linear Mode
