Disable the OnStar radio

Recently it's been in the news that OnStar can track you even it you do not subscribe to the service.

New York Times
As a default position, however, OnStar maintains the cellular connection after the subscription is canceled, a practice intended to collect data that could be useful to municipalities, for example, trying to improve traffic flow or to first responders attempting to determine the severity of a crash before arriving at the scene. Mr. Iyer said that there were related services that OnStar could offer in the future, like remote vehicle diagnostics.

C|net
Earlier, I referenced how OnStar collects and sells your data, even if you do not have a plan. Yes, that means you are still making money for OnStar even if you are not paying for it. The way it works is simple. There is a "soft" disconnect, in which a user will turn off the service, but it actually is kept available so it can be reactivated. OnStar admits, "Information about your vehicle may continue to be collected even if you do not have a plan." Uh oh. There goes the data, right back to all of those people listed above, including the marketers (which could include, but not limited to, insurance companies).

Regarding the soft disconnect, a GM rep stated, "It makes it easier to re-enroll customers, enroll new customers of used GM vehicles, and push out new systems to vehicles, even if they're not current subscribers." GM would not elaborate further as to why a soft disconnect was easier to reactivate, though.

When I bought the Monte Carlo I never activated the OnStar. I have a cell phone, I have Triple A and I have $240 a year in my pocket. When the button got pushed by accident and these Spanish voices came over the stereo speakers it gave me the creeps. I set out to neuter the thing (like most mods, it can be reversed) by simply disconnecting the radio control box.

In the 2006 Monte Carlo, the box is in the trunk, mounted on the back of the drivers' side rear wheel well. Pull back the trunk carpet and it's there.
OnStar box

You might be able to disconnect it by feel, my curiosity made me take the box off. Nut driver, please.
Nutdriver to Onstar

There's two plugs for power & data, two more for antennas. I assume one antenna is a GPS and the other is for the cellular system
Onstar plugs

Simply find where to unlatch the plug and pull it out.
 Muted Onstar

All the plugs have a press-to-release
Onstar Antenna plug

Coil up the cables
Cables

Replace the radio. Tuck the cabling back under the bracket.
Muted Onstar

Tuck the trunk carpet back in. Test for dead air. Check other systems. I've not seen any warnings since doing this a few months ago.
Blue Button do nothing