Disable OnStar without losing GPS and microphone

[A9G-Data-Droid]

To disable OnStar tracking without losing GPS and microphone you can disable the cell phone by blocking it's antenna.

Tin Foil hat for OnStar:
https://imgur.com/gallery/n00QKnH

SUMMARY

Parts:
1x Z Female to SMA Female antenna cable
1x SMA male 50 ohm terminator

Plug dummy load into onstar cell antenna port by reaching in through the hole behind the glove box.

[rhymeswithmogul]

I did this on my 2019 Bolt, to both antennas. GPS and location-based charging no longer work (as expected) but OnStar still says "OnStar Ready" when you press the button. I don't have a red light above the OnStar button, but I never had a blue light before, either; maybe that's model-year specific. Is there a way to check the 4G/LTE cellular signal from the infotainment system?

[A9G-Data-Droid]

There is a little icon. The best test is to attempt to use OnStar and see if the operator picks up the phone. What I found is that it has other ways of connecting. It can use WiFi and it also appears to be able to use the connection from Android Auto\CarPlay.

So while these measures give you more control, I ended up pulling the fuse at the fuse box. Please let me know what you see in your testing. This is a very strange topic. All we know is from testing.

[kallisti5]

Nice! A little warning though, some radio transmitters will suffer damage if the impedance of the antenna isn't enough. The recommended terminator should be fine, however don't get creative and shove foil into the connector or something