WHT Z06 Modifications: OnStar Upgrade

OnStar was optional on the C6 Corvette from 2005 to 2007 and standard from 2008 to 2013. In 2019 I decided to upgrade my navigation radio to gain an AUX input and my OnStar (aka VCIM) to gain factory Bluetooth. Here are some part numbers:

GM	Years	Details
15934199	2007	GPS: Fakra C (blue), GSM: mini-UHF
25909997	2008	GPS: Fakra C (blue), GSM: mini-UHF
20794960	2009-2010	GPS: Fakra C 5005 (blue), GSM: mini-UHF, Bluetooth
20794959	2009-2010	GPS: Fakra C 5005 (blue), GSM: mini-UHF
22867042	2011	GPS+GSM: Fakra D 4004 (bordeaux), Bluetooth
22867043	2011	GPS+GSM: Fakra D 4004 (bordeaux)
22898987	2012-2013	GPS+GSM: Fakra D 4004 (bordeaux), Bluetooth
22781076	2012-2013	GPS+GSM: Fakra D 4004 (bordeaux)

While I suspect any newer module is compatible with my car I found a 2012-2013 version (22898987) on ebay. It is a OnStar generation 9.2 unit (using the 3G network); my original 2007 module was only 7.0. OnStar announces its generation when you hold the white/phone button for 6 seconds.

The OnStar module and antenna (20781950) for my 2007 had separate Fakra coax connectors for GPS and GSM but starting in 2011, the OnStar GPS and GSM antenna feeds are combined into a single coax feed. It's probably possible to use a 2011-2013 module with the newer windshield antenna (22830110) but I have no interest.

In addition to the newer navigation radio you need to add the left side steering wheel switches to do things like pair phones or make hands free calls. The part number for this is 25862864. You also need a Bluetooth antenna (15938939) but used OnStar modules usually come with one.

OnStar Neutering

I had a trial OnStar subscription when my car was new but once it expired I disabled the VCIM module by pulling three of the four connectors. The factory service manual shows that C1 is the only connector with power so removing it would be sufficient. But you must must leave C4 connected because it is a high speed CAN bus pass through and removing it bifurcates this bus and literally prevents you from being able to start the engine.

After installing my 2013 OnStar/VCIM module I found a couple of websites that showed an even better way to disable OnStar; disconnect the cellular modem daughter card from the main OnStar board. Basically when you remove the cover and the main board you'll find reveal the modem card with a board-to-board jumper. Remove the jump, reassemble and OnStar no longer has the ability to use GPS to find your location or GSM to phone home. This method works for many OnStar modules including my 2014 CTS-V.

Previous Bluetooth Setup

In 2014 I added Bluetooth support to my car using a Bluestar II module made by Costar Technologies.

After moving some connectors from the factory OnStar module to the Bluestar the unit provided very good Bluetooth integration with the factory microphone and radio.

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Craig Leres