Factory NAV Experts step inside please :-)
Teching In
Joined: Jun 2013
Posts: 28
Likes: 0
Just some additional information for what it's worth.
Seems like the navigation works much better with a factory 20794960 VCIM OnStar module (2009 - 2010 Corvette with factory Nav) compared to my factory 15869895 VCIM module (2008 Grand Prix without nav)
The GPS signal is picked up within 30 seconds of my Grand Prix leaving the garage (Corvette VCIM) compared to 2-3 miles (sometimes longer) with my factory Grand Prix VCIM.
Factory 2008 Grand Prix dash wire harness
Factory 2008 Grand Prix GPS antenna in the factory location
Factory in dash navigation unit.
Factory 2009- 2010 Corvette VCIM with Bluetooth mounted in the 2008 Grand Prix factory location.
Seems like the navigation works much better with a factory 20794960 VCIM OnStar module (2009 - 2010 Corvette with factory Nav) compared to my factory 15869895 VCIM module (2008 Grand Prix without nav)
The GPS signal is picked up within 30 seconds of my Grand Prix leaving the garage (Corvette VCIM) compared to 2-3 miles (sometimes longer) with my factory Grand Prix VCIM.
Factory 2008 Grand Prix dash wire harness
Factory 2008 Grand Prix GPS antenna in the factory location
Factory in dash navigation unit.
Factory 2009- 2010 Corvette VCIM with Bluetooth mounted in the 2008 Grand Prix factory location.
Just some additional information for what it's worth.
Seems like the navigation works much better with a factory 20794960 VCIM OnStar module (2009 - 2010 Corvette with factory Nav) compared to my factory 15869895 VCIM module (2008 Grand Prix without nav)
The GPS signal is picked up within 30 seconds of my Grand Prix leaving the garage (Corvette VCIM) compared to 2-3 miles (sometimes longer) with my factory Grand Prix VCIM.
Factory 2008 Grand Prix dash wire harness
Factory 2008 Grand Prix GPS antenna in the factory location
Factory in dash navigation unit.
Factory 2009- 2010 Corvette VCIM with Bluetooth mounted in the 2008 Grand Prix factory location.
Seems like the navigation works much better with a factory 20794960 VCIM OnStar module (2009 - 2010 Corvette with factory Nav) compared to my factory 15869895 VCIM module (2008 Grand Prix without nav)
The GPS signal is picked up within 30 seconds of my Grand Prix leaving the garage (Corvette VCIM) compared to 2-3 miles (sometimes longer) with my factory Grand Prix VCIM.
Factory 2008 Grand Prix dash wire harness
Factory 2008 Grand Prix GPS antenna in the factory location
Factory in dash navigation unit.
Factory 2009- 2010 Corvette VCIM with Bluetooth mounted in the 2008 Grand Prix factory location.
The VCIM (OnStar module) has nothing to do with the GPS signal that the NAV receives with respect to actual navigation. C6 Corvette owners with the factory navigation have removed their VCIMs and replaced them with BlueSTARs to in an effort to get Bluetooh functionality; NAV features and functions remain the same.
There are two GPS antennas in the vehicle:
Teching In
Joined: Jun 2013
Posts: 28
Likes: 0
A little subjective? Maybe there's something else that you did not test. An outlier somewhere?
The VCIM (OnStar module) has nothing to do with the GPS signal that the NAV receives with respect to actual navigation. C6 Corvette owners with the factory navigation have removed their VCIMs and replaced them with BlueSTARs to in an effort to get Bluetooh functionality; NAV features and functions remain the same.
There are two GPS antennas in the vehicle:
The VCIM (OnStar module) has nothing to do with the GPS signal that the NAV receives with respect to actual navigation. C6 Corvette owners with the factory navigation have removed their VCIMs and replaced them with BlueSTARs to in an effort to get Bluetooh functionality; NAV features and functions remain the same.
There are two GPS antennas in the vehicle:
Teching In
Joined: Jun 2013
Posts: 28
Likes: 0
The VCIM was the only item changed and there was/is a significant difference between the two modules installed in my 2008 Grand Prix:
1) signal strength (no red slash)
2) length of time acquiring the signal after driving out of the garage
3) The ability to keep the GPS signal.
I posted the information as a courtesy only, the information was never up for debate. This was my results from my test!
Teching In
Joined: Oct 2018
Posts: 4
Likes: 0
From: Kamloops BC Canada
I just purchased a 2008 Grand Prix GXP and it has every option except engine block heater (don't care) and navigation. I ordered a factory ACDelco GPS/Navigation antenna and I will install it tomorrow in the factory location. I know I need to have the nav unit unlocked but I have a couple of questions.
Can anyone tell me (without guessing) what the 4th electrical plug is on the back of the nav unit? Port 1 and 2 are the factory radio plugins, port 3 is for the nav antenna and port 4 is for??
Once I install the nav unit and plug in the (3) know plugs will I need to install anything else to make the nav work as intended from the factory?
Thanks for your help.
Can anyone tell me (without guessing) what the 4th electrical plug is on the back of the nav unit? Port 1 and 2 are the factory radio plugins, port 3 is for the nav antenna and port 4 is for??
Once I install the nav unit and plug in the (3) know plugs will I need to install anything else to make the nav work as intended from the factory?
Thanks for your help.
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Registered User
Joined: May 2022
Posts: 1
Likes: 0
From: East Alton
hello all did anyone had good luck on finding the right length gps antenna for our cars and mount in factory location, i read the forums just want to makesure i get the right one just got my radio in mail needs software updated but dealer can fix that no biggy just need a good antenna part number i can buy asap
