Mystery Box Behind Glove Box

[Caman96]

So that’s how they’ve been tracking you all these years.

 

[xXxPARAGONxXx]

Note the covered sticker in that link...

Visible in this one. It's OnStar, and has nothing to do with amplification of anything related to radio audio.

Good eye.

 

[AK49BWL]

In some of the wiring diagrams between 98-99 various models of GMT400 (Suburban, Escalade), this module is (barely) included - it has connections to all three available data lines (Class2, E&C, and UART Serial from the Airbag unit), the power locks circuits, and does have outputs going to the radio's AUX input cable. But that's all I can find about it.

Connections to radio:

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Data lines:

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Notice its connections directly to the door lock and unlock switches (second module down):

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[Caman96]

Everyone seems to think it has something to do with radio amplifying.

I mentioned amp because you said you had a Bose System.

 

[HotWheelsBurban]

I didn't know BOSE was available on any 400s besides Escalade and Denali....

 

[Caman96]

Its connection to radio was probably just to hear dispatcher speaking back to you. Apparently it unlocked your doors too.

 

[AK49BWL]

I mentioned amp because you said you had a Bose System.

I promise that wasn't a dig at you specifically - even searches of the PN on Google bring up pretty much "Radio Amp" this and "radio amp" that lol. Seems like nobody really knows.

 

[HotWheelsBurban]

Its connection to radio was probably just to hear dispatcher speaking back to you. Apparently it unlocked your doors too.

Yup OnStar has a mini speaker over the driver so their dispatcher can talk to them in the event of an emergency. Our Denali had a cell phone service with them too, though we never used it and didn't renew it after the trial period.

 

[Caman96]

I promise that wasn't a dig at you specifically - even searches of the PN on Google bring up pretty much "Radio Amp" this and "radio amp" that lol. Seems like nobody really knows.

Yeah, no biggie, I did think it was an amp.

 

[JohnZ71]

uncommon for a suburban to have OnStar in 99. Pretty cool! Obsolete of course, but cool nonetheless. I've been looking for onstar components to add to my Tahoe just because it was a cool option plus i like the look of the rear exterior antenna.