Aux Input Static

I have been wanting a direct auxiliary input for my xm radio for a long time. Well I finally broke down and bought one - a PAC Auxbox from cardomain for $75. Installation was simple and it comes up as the cd changer on the hu. However, I have lots of interference when using it. If the key is off (using retained power), there is the least background noise - just a beeping sound every second or so. When I turn to the key to acc or on (with the engine off), a second sound is introduced, like a constant static. Then, when the car is running, the static sound degrades to a skippy-like static that fuzzes several times per second. Anyone add an input yet and run into these problems? I'm thinking it might be a grounding issue or it could be that I used a "t" cable at the back of the head unit to give me the changer interface. This interface is 9-pin rather than the typical trunk one of 10 pins. The 9 pin one is what was used on chevy's, whereas olds and buick typically have 10's. But I'm not sure if that would be the problem, as the sound and all still works. Another note, the interference is still there after unplugging the auxbox from the interface, indicating the problem probably isn't in the box. Then, after a few seconds, it goes back to radio as it no longer senses the "changer." If someone can provide me with a wiring diagram for the 32 pin harness at the back of the radio. Also, a diagram for the 10 pin changer harness and the 9 pin one I'm using would be helpful. Thanks in advance.

Anybody????? I would like to work on this this weekend. If I could have the wiring diagram for the 32 pin harness and the changer harness (10 pin and the 9 pin version), it would be most helpful. By the way, forgot to mention, it's an 01, so it's the old E&C bus. I also have the Bose system and Onstar. Onstar no longer works (grrrr) because of the t-harness I have hooked up, so I need to make it work, cause I'm paying for it. Please help!