Others have said it is impossible to remove the connections from the OnStar unit without removing it but this is not the case. If you grab a medium-sized flathead screwdriver, you can use that with leverage from the OnStar bracket to pull them out easily. Just line up the screwdriver with the clip tab, then pull the screwdriver towards the steering wheel - the connector with slide right out.
On the 2008 Equinox, the plastic in front of the OnStar unit has a perfect sized "cubby" for the BlueSTAR - I just stuck a small piece of 3M two-sided tape and pressed it in there to keep it from rattling around.
