Adding factory Bluetooth to a GMT800

JoshH

Daggum farm truck
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Feb 14, 2007
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As stupid as it may seem to some, I have a strong personal preference for OEM radios and controls. So much so that I went through the trouble and expense of swapping out my factory head unit and Bose amp for a Bose LUX/TNR Nav head unit and amp from an Escalade. A few years ago I did swap the factory XM module for an iSimple module that allows me to stream bluetooth audio, but I have recently had a desire to have handsfree bluetooth phone calls. A quick google search pulled up a video on youtube showing how to add this capability using OEM parts. It isn't cheap, but it is the only option I have found. The module has been discontinued, but the dealer I use for parts said there are plenty in stock in Michigan. I'm hoping the install is fairly straightforward. I will keep this post updated with my results. Here's the video for those interested.

Source: https://www.youtube.com/watch?v=QKB0JUGdLA8
 
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TheBac

Why do I keep doing this?
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Apr 19, 2008
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This would've been right up Bens alley if he were still around.

Doesn't surprise me one bit that a t-blazer vcim would work. I'll also bet it'll work with 2003-up, not 04-up like he said.
Josh, if you find a couple with antennae, I'll buy the second one off you.
As for stock radios, my lux bose setup is still louder, richer and clearer than any other oem stereo I've ever heard, before or since.
 
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fl0w3n

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Jan 8, 2015
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I'm at work so I can't watch the video right now, but I'm wondering where the mic input comes from?

I have a Pioneer with the stupid black little microphone clipped up by the mirror/headliner, but I'd like a more factory OEM appearance/better quality. I've wondered about using the On-Star mic that goes in the head liner, but I don't know if it's better quality or if I could get an aftermarket one to fit in there.
 

fl0w3n

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Jan 8, 2015
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That's what I figured. I wonder how the quality is.

With my Pioneer setup I've had multiple people comment how it sounds like I'm driving, and one or two people say they couldn't even understand me because of poor quality/background noise. I'm wondering if the OnStar mic would prove to be better quality?

I know on my old work F150 the built in Sync mic would sometimes get garbled, but if I "rubbed" it once while on a call, it would somehow fix it. So I'm not sure if it's a software logic thing to cancel out background noise or a purely hardware issue I'm having now.
 

1FastBrick

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Dec 1, 2016
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In for the results. I knew about the module but was not aware it needed an antenna for it.
I didn't know there was any stock either. I was always just told it was discontinued And never had any luck finding a Used one.

definitely in for the results, part numbers, and hopefully a few pictures.
 

DAVe3283

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I have the iSimple Bluetooth setup in my Suburban. Requires a 2nd microphone (I put it next to the OnStar mic) but it works great with the TNR800. No complaints about call quality from either end.

I'm very interested in how this works out though.

Sent from my ONEPLUS A6013 using Tapatalk
 

KyleC4

Tech
Dec 30, 2016
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I’m definitely on the factory head unit preference side. It always appears to be the cleanest look. Will be checking back to see how yours comes out Josh
 

DeDiesel

King of Mars
Dec 21, 2011
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I tried the iSimple and BlueStar CoStar bluetooth modules but I was not happy with the sound quality, reliability as well as they interferred with flashing my ECM.

I've done several of these VCIM installs on GMT-800 & GMT-900's and they all worked flawlessly with great sound quality. They use the factory OnStar mic and are easy to use but not so simple to install. The OnStar module with Bluetooth for the GMT-800 trucks that work are out of 2009 GMT-360's ( Trailblazer, Envoy, Rainer, Saab 9-7x etc.) I bought mine on eBay for under $100. You need to have the VCIM Module and Bluetooth Antennae

GMT-800 VCIM Part Numbers
25965167
20782641
20830941
20850446
22829371

Bluetooth Antennae 15938939

GMT-800's are not such an easy install as you have to take a fair amount of the dash apart and make a bracket to install the new module in the factory location behind the glove box and airbag. If you want to try it out before taking the dash apart you can disconnect the two connectors from the original OnStar module and feed them down to the passenger foot well and connect the new OnStar Module. I left mine this way until my wife complained too many times about kicking it.

GMT-900's are a much easier install and you need to have the VCIM Module, Bluetooth Antennae and steering wheel controls wiring harness. I installed it on a 2007 NBS

GMT-900 VCIM Part Numbers

25990227
20787642
25990228
20787643
25984444
20783877
25984445
20783878
20787107

25851951 - Audio/Bluetooth switch/ steering wheel buttons
15938939 - vcim Bluetooth antenna

OnStar® (VCIM) Module) found in Models:
2009 Buick Enclave
2008-2009 Cadillac CTS, CTS-V
2009 Cadillac Escalade, Escalade ESV
2009 Chevrolet Avalanche, Silverado, Suburban, Tahoe, Traverse
2009 GMC Acadia, Sierra, Yukon, Yukon XL
2009 Saturn OUTLOOK, VUE
All Equipped With Gen 8.0 OnStar® (RPO UE1) and Navigation Radio (RPOs U3R, UVB, U3U, UAV or UZR)

Issue with a used VCIM is it still have the VIN of the vehicle it came out of so if you use OnStar (I don't) they will call you by the previous owners name and reference the donor vehicle. However, OnStar will reprogram the VIN if you tell them your original VCIM died and you got a replacement.
 
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