Where is Onstar unit located on 2005 Tahoe

[robertscottcostello]

I've taken out the radio, looked under the glovebox, looked above the glovebox, and searched everywhere online. Where in the heck is the Onstar for this car, and how do I get to it? I bought one of those BlueStar units to install bluetooth, and I'm dying to use it.

Thanks in advance.

Rob