It’s actually quite inexpensive these days to add factory-spec Bluetooth to “older” cars from the mid-2000’s. Here’s how to do it on many 2007-2011 model year GM cars, and 2007-2014 trucks.

GM says you can’t add factory-spec Bluetooth to your car if it didn’t come with one. They’re wrong, but only because you have to break their rules to get the job done.

Important Warning: Your car is probably already out of warranty. But this could void the warranty on components involved. Either way, I take no responsibility if this causes your car to melt… nor do I take any responsibility if you or your first-born are imploded… nor do I take any responsibility for anything less-bad than that which could happen.

In 2009, and continuing through about 2014, General Motors offered built-in Bluetooth on some of its cars through the OnStar module. For identical cars built before that, GM says it’s impossible to retrofit. But in reality, it’s just an upgrade GM didn’t want to offer to dealers as a part upgrade.

This process works with most 2007-2011 Model Year (MY) cars, and 2007-2014 trucks. Even if the same car exists before 2007, it probably won’t work. GM did an upgrade to the GMLAN networking firmware in their Body Control Modules (BCM) that enables what they marketed as “advanced voice controls” – that feature is key to enabling the Bluetooth module. Unfortunately, without it, you basically have to upgrade your Body Control Module… something very expensive and not recommended (replacing it with a newer/untested variant and firmware can cause epic problems as it communicates with almost every electrical component in your car).

Why do this mod? GM Bluetooth taps into the integrated microphone that comes standard on most GM cars. GM’s microphone is pre-calibrated for excellent audio reception. With the exception of convertibles, most find it to be one of the best Bluetooth solutions for your car out there. Plus, it is fully integrated with the OnStar and steering wheel audio buttons – so everything appears (and performs) like factory.

Downsides? A couple. One, you won’t get A2DP Stereo Bluetooth. Two, you will have to take your car apart, or pay your dealer to do it. Three, it can cost you up to $100 (around $100 for the parts, and around $100 for the optional firmware reflash). Your dealer may charge up to $100 to install it, too.

Get the Right Gear

To do this mod, you need a Bluetooth OnStar module. This used to be a few hundred bucks… but it isn’t anymore. You can get these used for about $100. Sometimes even less.

The OnStar module needs to have a Bluetooth dongle, too. It’s a small attachment antenna that clips to the back of the OnStar module. Most pick-and-pull versions you will find have the antenna still attached.

Here’s a list of the cars (and module part numbers) you need to do this:

Delta Platform Cars (Chevy Cobalt & HHR, Pontiac G5, Saturn Astra) – 20833261, 22740323 or 20837492 (Strongly suggest 22740323 (2011), followed by 20833261 (2010) as they have RemoteLink)
Epsilon Platform Cars (Chevy Malibu, Pontiac G6, Saturn Aura, 9-3 See Below) – 25817241 (2009-2010), 22740323, 20833261, 22740323
Sigma (II) Platform Cars (Cadillac CTS & STS, First-gen SRX is Unverified) – CTS: 20837492 STS: 20793309, 25983291 or 25807050
Kappa Platform Cars* (Pontiac Solstice & Saturn SKY) – 20793309, 25983291 or 25807050 (DO NOT USE 20833261 with Kappa – GM interchanges listing this are erroneous)
Lambda, Theta & Zeta + GMT900 / GMT9XX (Buick Enclave, Cadillac Escalade, Chevy Avalanche, Suburban, Silverado, Tahoe, GMC Acadia, Sierra, Traverse, Yukon, Saturn Outlook, SAAB 9-3*, Hummer H2, Pontiac G8) – 12842801, 20787107, 20829984 (may have RemoteLink – replaces the prior two), 2598444, 20783877, or 20827036 (20827036 is the newer module that replaces the prior two… and supports RemoteLink)

Other part numbers may work. If you have verified success stories, post them.

* Kappa Platform Note: Some very, very early Kappa platform cars that are sold as 2007 MY cars will not work with this procedure. They were shipped, basically, with pre-release firmware that did not have the “advanced voice control” functions needed to make Bluetooth work. You would need to deploy a new Body Control Module to make those cars work. Check your manufacturing date if you have an ’07 Solstice or Sky, make sure it wasn’t one of the first few hundred validation units off the line.

* SAAB 9-3: The 9-3 is an oddball. It is Epsilon platform, but since it was designed in Sweden, the car’s OnStar was a major afterthought. Like the G8, it uses the truck VCIM as a result. The link in the list above takes you to a SAAB forum which outlines the various wires you may have to run, depending on which radio you have. It’s more difficult on the 9-3, and it probably cost SAAB hundreds of thousands (at least) in wasteful engineering.

For the Camaro and other Global A cars – some of which were sold concurrently, you need to add a PDIM module. That’s beyond the scope of this article… but it’s actually much easier to do. Some of these models (like Traverse) were upgraded to Global A wiring and circuitry mid-generation… so you need to check your specific year to see if you need a VCIM or PDIM. When in doubt, ask.

European Models (Opel/Vauxhall cars): Because Europe didn’t have OnStar VCIMs, they created a module very similar to the BlueSTAR module (described below). The Holden part number for Commodore VE is 92196020, for example. Similar to the North American models, you need the “advanced voice control” firmware that started to roll out in 2007. You should make sure your car has the microphone and audio control buttons (on the steering wheel) before attempting this one. I have near-zero experience with EU/Oz deployments, but please post comments with your experience!

Getting it Programmed

Installing is specific to your car. A dealer should be able to do it for you. Some won’t since GM issued a directive to not do this. You can do it yourself, but on some cars it is quite involved.

Here’s the catch. OnStar modules are coded to the VIN of your car. So when you plug in a different OnStar module, you’ll notice your OnStar LED has turned red. What’s going on here is that your car realizes the OnStar module wasn’t programmed with your car’s VIN.

If you’re fine with the OnStar light turning red, odds are you don’t need to do anything. In most cases, the OnStar service will still work – the light simply stays red to alert you that the module doesn’t match the vehicle’s VIN. Most people that have issues with OnStar, wound up using an incompatible VCIM (even with an incompatible VCIM, Bluetooth does often work).

That’s a major reason why I wrote this guide… people were buying the wrong VCIM part number – for their car – and wound up not being able to use OnStar anymore.

The one gotcha in all this, is that OnStar will think your vehicle is whatever car the module came from. For example, my 2008 Sky appears to OnStar as a 2009 Sky. My 2009.5 Pontiac G6 appears to OnStar customer service as a 2011 HHR. If your vehicle is ever disabled, and you need roadside assistance, you may want to alert the OnStar dispatcher that your car is different than the one on the account. Just tell them you did a VCIM swap, and they should (emphasis, should) get it.

Wait, there’s more. Many 2009 OnStar 8.0 VCIM’s originally shipped from the factory with a few bugs. The biggest is battery drain. There’s a TSB out for it. Good luck getting your dealership to update a VCIM from a completely different car, that doesn’t even match the part number of your car. Plus the latest firmware will improve Bluetooth connectivity with your phone.

The good news here is Chris White of White Automotive and Media Services (WAMS for short) can reprogram the VIN, and at the same time update the firmware in your OnStar module. Your OnStar will work, your LED will be green, and you’ll have the latest firmware for Bluetooth pairings.

Needless to say, I highly recommend it.

If you’re daunted by install, having WAMS flash it also gives you the assurance that it will “just work.” Most dealers will install a VCIM that is pre-programmed for $100 or less. Just tell them it came from somewhere in Detroit, and to test it before closing the car up.

Could this mod keep my car from starting?

I’ve been asked this a few times. Back in the day, GM touted that OnStar modules were an effective anti-theft device. They touted that if the OnStar module was tampered with, that your car woudln’t start.

Well, kinda. Today the Global A cars are much more secure. But these older cars… not so much.

Turns out, your car will start and work provided *any* OnStar module is connected. All the Body Control Module does, is verify that the lead wires to the VCIM are feeding power and are grounded. You can even pour water over a VCIM, ruin it, and plug it into the car – it will still start up. Speaking from experience there…

With a Tech 2 service tool, you can go one step further and turn off the OnStar feature completely – which will let you then run without any VCIM. Which means your stolen car’s vehicle tracking can be disabled with a $299 service tool, and a socket wrench.

Like I said, modern GM cars are much more secure.

RemoteLink

Here’s one cool bonus. If you have a Delta or Epsilon class car and add OnStar module part number 20833261 or 20827036, you have an OnStar 8.2 module.

Note: I’m probably missing some 8.2/RemoteLink modules… please post in the comments with others!

With OnStar 8.2, GM backported basic RemoteLink functionality. So you don’t need to call OnStar to lock/unlock your phone… you can use the app. Sounding the horn also works too.

It’s not everything that OnStar 9.0 supports on your phone, unfortunately. Remote start isn’t available, nor is location tracking. Mileage and fuel status do work.

I actually find myself using it quite a bit. You can make sure your car is locked from anywhere, instantly. Plus I can get precise gallons left in the tank, something the car doesn’t tell me without an OBD2 Bluetooth tool.

A Word About CoStar

I should take a moment to credit CoStar and their hard work with the BlueSTAR module. BlueSTAR is a unique module made by a prolific hacker(s), who took GMLAN interface code and managed to create an OnStar module replacement, which adds Bluetooth. They’ve even added mono A2DP through waves of firmware updates.

So, why do I use GM’s solution instead? One, I like OnStar. Two, GM’s solution is admittedly a bit more reliable. Three, and most relevant at this point, a used OnStar VCIM with Bluetooth is actually now much cheaper in aftermarket part supplies. Even with WAMS flashing service, you can get that done in under $200.