(updated 4/1/22)

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Introduction

 In 2009 GM offered Bluetooth Handsfree Calling to the Corvettes.  New steering wheel controls were added, making it easy to pair your mobile phone and use the factory audio system for clear, integrated communications.  There are lots of inexpensive Bluetooth devices available for not only handsfree calling but also for high quality music streaming, but no aftermarket devices are as nicely integrated or as easy to use as the factory Corvette solution.  The OEM Bluetooth will not do music streaming - only handsfree calling - but it is a very desirable option that most Corvette buyers chose when they ordered a new Corvette.

For years, I had been advising C6 owners that adding factory Bluetooth was not practical because I mistakenly thought that extensive wiring changes were necessary to make it happen.  But recently I learned from a few Corvette owners on the Corvette Forum that not only is it possible, but it's quite easy.  All you need are the right GM parts, and you can add factory Bluetooth to any C6 Corvette.  I decided to research the options available and explain them on this website so you can decide if you want to add this very convenient feature.

What made this option possible was the upgrade from Generation 7 to Generation 8 of Onstar.  The VCIM (Vehicle Communication Interface Module), otherwise known as the Onstar module, has been a standard feature of all Corvettes since 2008.  It was optional in prior years.  Subscription was free for a limited time, offering a number of convenience and safety features in a new Corvette.  A GPS and a cellular antenna on the windshield allows communication with Onstar and allows tracking of your vehicle using the GPS features.  It also allowed handsfree calling through the Onstar Calling feature in which you purchased minutes for your unique Onstar phone number.  Some owners enjoy those features and others dislike the tracking ability, but subscribing to those features has always been optional once the free trial ended.  

But the Gen 8 Onstar modules began offering a Bluetooth connection to your mobile devices for handsfree calling, independent of the Onstar Calling feature.  So you could use your own mobile device with your own phone number and contacts for free - no subscription necessary.  All you do is pair your phone (or phones) and use the new steering wheel buttons to initiate and end a call.  The Onstar microphone on the left windshield support is used for speaking and the automatically muted audio system is used for listening.

This Bluetooth feature can be added to any C6 Corvette.

UPDATE ON 4/1/22:

This modification involves replacing the VCIM, otherwise known as the Onstar module, in your Corvette.  Some of the pre-2008 Corvettes were not ordered with Onstar.  If you don't have a factory Onstar module, you have no VCIM to replace.  At this time, I don't have a solution to add factory Bluetooth to non-Onstar Vettes.  Maybe later this year, but for now a couple of other Vette owners are working on it.

What You Need to add Factory Bluetooth

PARTS DETAILS

1. The VCIM (Onstar Module)

Here is my original VCIM from my '07 Z06:

Notice it has two antenna connections.  The one on the right is for cellular communication to and from Onstar.  The one on the left is the GPS connection so Onstar can locate your vehicle.  Both coax cables are connected to the VCIM and connect to the combination Cellular/GPS antenna on the windshield.  Here is my original Onstar antenna and the windshield bracket on which the antenna is mounted.  Notice the two connectors.

If you tap the antenna near the mirror towards the right, it will slide off of the clips.  Pull it down and you will see the two connectors.

It is only necessary to remove and replace the antenna if you decide to use a Gen 9 Onstar module and want to communicate with Onstar.

Here is a Gen 8 Onstar Module from a 2010 ZR1:

Notice it has a connector for cellular communications and a connector for GPS, like the original Gen 7 VCIM.  But it also has a Bluetooth antenna.  You can use this module with your original windshield antenna that has the two coax cables connecting to it.

Here is a Gen 9 Onstar Module from a 2013 Z06:

Notice it lacks the cellular antenna connector, but it has the Bluetooth antenna.  This module requires the newer windshield antenna shown here:

NOTE:  The antenna connections are for communicating with Onstar.  If you elect not to communicate with Onstar or subscribe to a service, simply leave the antenna cables disconnected.

VCIM WIRING

 There are four electrical connectors to the VCIM.  Fortunately, the wiring is the same for all C6s, so you can interchange modules between cars.  HOWEVER, each module is uniquely identified by the VIN number of the original car.  So if you call Onstar, the description of the original car will show up in their system.  Keep this in mind as you install a used VCIM from another vehicle.  ALSO, note that Connector 4 (which plugs into J4 on the module) passes the GMLAN communications signal through the module.  For those of you thinking about removing the Onstar module for privacy reasons, you CANNOT remove Connector 4 without jumping Pins 2 and 3 and Pins 8 and 9 - the car will not run without Connector 4 in place.  But this website is about Adding Bluetooth, so you MUST have the VCIM powered up for Bluetooth to operate.  There is a VCIM Addendum below to show the wiring details.

2.  The RADIO

For factory Bluetooth to work, you need a radio that is compatible with the steering wheel voice controls and the Bluetooth VCIM.  This means you will need at least a radio out of a 2009 or later C6 Corvette.  An excellent choice is the factory USB Nav radio from a 2011-13 Corvette.  This radio (GM part number 20856087) is not only compatible with the Bluetooth functions, but it also provides both a USB and an auxiliary input via a 3.5mm jack in the console, very nice features indeed for connecting your music device to your audio system.  This USB Nav radio can be installed in any C6 Corvette, whether or not your car is equipped with a factory Nav or non-Nav radio.  Here is the link to the website page for installing the USB Nav radio:

http://www.kawal.net/USB%20Nav.htm

3.  The STEERING WHEEL

Since you likely wouldn't be reading this if you already have factory Bluetooth, I'm guessing your car doesn't have a steering wheel with the voice control buttons on the left.  Here is a 2012 steering wheel without the voice control buttons:

Here is an earlier style steering wheel without voice controls:

Yours is likely one of the above two styles.

But you need one of these, with voice controls:

If you have an automatic transmission, with paddle shifters, you'll need the above version with the paddles.

By far, the simplest way to get the steering wheel compatible with Bluetooth is just to upgrade your steering wheel to one with voice controls.  Choose one with the features you need (with or without paddles) and the color and texture of leather you want.  Any steering wheel with voice controls will work.

If you want to keep your original steering wheel, it's possible to add voice controls.  There are clever ways to do this, because all the voice controls do is add a couple of switches and resistors to signal the radio to connect to Bluetooth.  One savvy owner even programmed his steering wheel controls to do different functions than originally intended.  And you could add small push buttons on the back of the steering wheel to control Bluetooth.  For most owners, however, you will at least need the left hand voice control switch assembly (GM part number 25862864).  You will then need to either modify your right hand radio switch or buy a new switch (GM part number 25862865) with the additional pin connector.  Finally the steering wheel harness will have to modified to connect the left and right switches.  These harnesses are unfortunately not available to purchase from GM, so you need to find a suitable used one or figure out a solution yourself.  The RPO option code for Bluetooth is UPF.

A Steering Wheel Addendum is provided below showing the wiring schematics for non-Bluetooth steering wheels and Bluetooth steering wheels.  Also shown in the addendum are details for removal and modification of your steering wheel.

There are lots of used C6 steering wheels available in the pre-2012 style.  Find one you like with voice controls and you're set.  Just be sure it matches your transmission with or without paddles.  Some owners have used a paddle shift steering wheel with a manual transmission by removing the paddles - that works.  And you can rob another used steering wheel for the controls and wiring harness to modify your own - that works too.  For the late style 2012/13 steering wheels, you will likely have a problem finding one.  They have been discontinued by GM and unless they bring them back, there are none available in the entire country.

4.  The Onstar Microphone

If you have this microphone you're all set:

If not, click HERE for how to replace it to get much better performance.

VCIM Addendum

Here are some schematics from the 2007 Service Manual for the VCIM wiring:

And here is the schematic for a 2013 Corvette:

Note that the only difference between the 2007 VCIM and the 2013 VCIM wiring is the single coax cellular/GPS antenna and the addition of the Bluetooth antenna

Replacing your Onstar Module

The earlier C6s have their Onstar module near the back of your car

except for the Z06's, which had the VCIM under the passenger seat.  Here's a photo of my module from my Z06:

I moved it when I installed power seats to the location of the Onstar module in the later Corvettes, above the passenger footwell Fuse Panel:

In the later Corvettes, a plastic bracket is used to hold the VCIM in place:

The newer Gen 8 and Gen 9 Onstar modules are thinner than the old ones, so they will fit in this bracket.

To have access to this area above the fuse panel, you will need to remove the plastic panel with the light in it.  Towards the top of the photo below you will see a plastic pin.  This locates the panel on the firewall above the fuse panel.  To remove the panel, use a flat tool to pry down the two plastic fasteners shown near the bottom of the photo.  That will release the panel and let it fall.  Disconnect the light from the panel and remove the panel.  You should now be able to see the Onstar module area.

Wherever you find your module, unplug the four connectors, then the two antennas.  

A small screwdriver will help you separate the white plastic connector cover on the cellular antenna.  

The GPS antenna has a small latch.

Plug the four connectors into the new module with Bluetooth.  They cannot be inserted in the wrong place.  

Connect the antenna wires to the appropriate location on the new module.

If you have a Gen 9 module, connect only the GPS antenna and you'll need to replace the windshield antenna with the newer single coax antenna.

Note that these antenna connections are only necessary if you plan to communicate with Onstar and perhaps subscribe to their services.

Steering Wheel Addendum

Here is the steering wheel controls schematic for a 2007 steering wheel without voice controls:

The wiring shown above was used in all 2007 and later C6 Corvettes without the UPF Bluetooth option.  The right control switch is GM part number 15942358.

In 2009, the UPF Bluetooth option was added.  For those Corvettes, the schematic below is used:

Note that in the non-Bluetooth steering wheels (shown in the top schematic), the right (radio) control switch has a four pin connector.  But the Bluetooth (Voice Control) steering wheels (bottom schematic) have a fifth circuit (5 pin connector) necessary to tap into the resistor series.  This allowed adding the second (left) switch for voice controls by adding two more resistors to the series.  The 2009 radios were also upgraded to allow the reading of the additional signals for the additional commands.

STEERING WHEEL REMOVAL

To replace or modify your steering wheel, here are a few suggestions that the Service Manuals omit.

First you must remove the steering wheel airbag module, so to be safe, remove the negative terminal on the battery or at least pull the airbag fuse:

See the missing fuse towards the right, just below the blue 15 amp fuse - that's the Airbag fuse location.

Removing the airbag module is about a 30 second job, IF you know how to do it - and the Service Manual isn't too clear.

First, point the steering wheel straight ahead and you'll see some small holes on either side behind the steering wheel.  The manual says turn the wheel so one is at the top, but it's easier to keep it pointed straight ahead.

You'll need a 5/32" or 1/8" punch or something similar with a blunt end.  Push the punch straight into the hole with it level to the ground, but first here are some photos to show how the airbag module is attached:

There are two of these locking pins on the airbag module, one on either side.

As you push the airbag module onto the steering wheel, a wire spring pops into the groove in the pin.

Here's the wire spring in the hole for the pin:

A view from further out:

To release the airbag, you must push the wire spring towards the center of the wheel.

See the wire spring below the round hole?  It's been pushed to the right with the punch shown below..

Here's a photo of the spring pushed, so the airbag can be released:

Keep the punch horizontal, straight toward the center, and you will push the spring to unlock the airbag module.

You'll have to feel around a bit with the punch until you feel the spring.

Pull gently on the module on the side you release, then simply do the other side the same way.

When you release the module, lay it face down in front of you:

In the photo above, the yellow locks have been pried up from the two connectors.

To release the connectors, squeeze the tabs inward.

Here's one connector removed:

Set the airbag module in a safe place and your steering wheel will look like this:

Unplug the white connector and move the wires away from the nut holding the wheel in place.

You'll need a 21mm socket to remove the nut, but here's a trick I learned many years ago for removing a steering wheel.

(Instead of a puller, this works most of the time.)

Loosen the nut quite a few turns, but DON'T remove it.

Now pull hard on the wheel, first left, then right.

Do that a few times and it will usually pop off against the loosened nut.

Then simply remove the nut and the wheel.

STEERING WHEEL WIRING

Depending on which steering wheel you have, the wiring is quite different between models.  A manual transmission steering wheel is much simpler than one with paddle controls.  And one without voice controls is much simpler than the voice control model.

Here's a wiring harness for a manual transmission wheel without voice controls:

The red connector is for the horn and the 4 pin black connector is for the right switch.

Now compare that simple harness to one for an automatic transmission with voice controls:

In the photo above, the horn assembly is still in place, but look at all of the wiring on both sides of the wheel. 

Here's the wiring for the right side:

The brown connector is for the right paddle switch and the black connector (hard to see) is for the right radio switch.

Here's the wiring for the left side:

Although I don't recommend this unless you're really good with wiring harnesses and connectors, the following information provides details for the steering wheel components in case you want to modify your steering wheel.

For the new 2012/13 steering wheels, you first need to remove the left and right bezels:

They are plastic, but you can pry them off carefully.  They are NOT individually replaceable, so do NOT break them!

Here is the left switch being removed:

and the right switch:

Two Torx screws hold each switch in place.  Older style steering wheels don't have the plastic bezels.

Here are the left and right switches from a non-voice control steering wheel (top) and a voice control steering wheel:

and the backs of them:

The right switches are NOT the same for a voice control wheel and a non-voice control wheel.  The right VC switch has 5 pins and the non VC switch has only 4 pins.

Here is the connector for the right VC switch:

The extra green wire connects to the left VC switch.  

(See the schematics near the beginning of the steering wheel addendum section.)

Here are photos of the left VC switch connector:

Note this is a 7 pin connector but only four wires.

Not only is the wiring different, but manual transmission wheels are different from those with paddle switches:

For my own '07 Z06 I have a 2013 manual transmission steering wheel and I needed to add voice controls.  The only 2013 wheel I could find was for an automatic, so it had the paddles.  That required me to swap the switches between the two wheels, but I also needed to modify my wiring harness to accommodate the new VC switches.  It was a LOT of work!  I would highly recommend you find the correct voice control wheel for your car, since it's a simple job to remove the wheel and reinstall a new one.

Here's one last photo of my car with the steering wheel off:

All you do is remove the air bag, unplug the connectors, and remove the 21mm nut, as described above.

Stick the new wheel on and you're done.

Helpful GM Part Numbers

Click HERE for a 12 page description of the Onstar System from the Service Manual in .pdf format

Antenna Addendum

For those of you who want to connect to Onstar and use the Generation 9 VCIM, there is some additional work you have to do.  The original Gen 7 and Gen 8 modules have two antenna connections:

The one on the left is the GPS antenna and the right one is for cellular communication.  Notice the two connector indexes on opposite sides of the GPS connector:  

Two coax cables connect to the module and then to the original windshield antenna:

The Gen 9 modules have only one connector:

Notice the connector indexes at right angles to one another.  A new dual purpose antenna using a single coax is used:

You have two coax cables connecting the module to the antenna, so you think well, just use one of them.  

It's unfortunately not quite so easy as that, because of the connectors on the two coax cables.  

The cellular coax has a push on type connector for the module end and a red connector at the windshield:

So that cellular coax won't fit either end - at the new module or at the new antenna.  That cable can't be used.

So you think just use the other (GPS) coax with the blue connectors at either end.  Not so easy either because the red and blue connectors are indexed differently.  It's hard to see in the photos, but the red connectors have their indexes at right angles to each other, while the blue connectors have the indexes opposite each other.  Both the new module and the new antenna have connectors with indexes at right angles, so the coax with the blue connectors won't fit on either end - both the module connector and the new antenna connectors have to be modified.

Fortunately, it's easy to modify them.  On the new antenna, use a utility knife to cut away the plastic index as shown:

On the Gen 9 VCIM, use a file to grind off the aluminum index so the original GPS coax will fit.

Once you modify those connectors, the GPS coax will fit on both ends - here's the connection at the windshield:

Once you get the new antenna connected you can push the Onstar button and call them up.  They will ask your name, assuming you are the owner of the Corvette the VCIM is from.  While they can easily change owners, they can't change the VIN number of the car in their system.  In my case, they see "my car" as a blue 2013 Z06.  I explained that my car is actually a yellow 2007 Z06 with a different VIN number, but their system has to remain with the same vehicle identification.  I still have the option of subscribing to Onstar with whatever benefits offered for my 2007 Corvette.

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