Ok. Sorry for late response, but I was not getting any notifications via email that the post had been responded to.

Jim,

The car is a 2012 GS 1LT. I installed an OEM nav system on the car (an oem system from a 2012 as well) after having the car for ~ 5 months. Car had 3,000 miles at time of installation and now has 6,000 miles. After installation of the nav system, I had the dealer re-flash the car in order to deactivate the anti-theft on the nav. After having this done, the Nav worked perfect. The nav position arrow would "rotate" as it should and track my cars movement and position as it should. Then after a few days, it just stopped. I don't know what happened. Now the arrow will not rotate. As I mentioned before, the arrow will move backwards, sideways.

There are no other issues with the car. No error messages, etc. No power issues. I have not done any other mods to the car other than the nav installation. I have no other issues with the nav at all. Everything else works as it should including the usb/aux.

I have spoken with a couple of guys that installed oem navs onto their cars and they did not have any issues, so I figured it would work with mine.

Thanks.

John

 

Understand what you are describing. It sounds like there is an error (software bug/hardware issue) inside the Nav Unit Electronics. It may require pulling the unit and sending it out for repair. Since you had it installed after purchasing the car it probably isn't covered by a warranty of any kind unless the dealer purchased the unit from GM and installed it for you. There are some code updates that are available for earlier units but you would have to check with a dealer to see if there are any for the 12 units. When I say code updates I am not talking about Navigation updates but the actual code that runs inside the unit and makes the display work, the sound work, etc. A rebuilt NAV unit from GM will run about $1300. I had the one in my 08 replaced last year under GMPP due to it going crazy, opening the display, locking in the DVD, switching radio stations on a random and frequent basis. My dealer tried updating the code but the unit kept doing the same thing so replacement was the only option.

If you can find the supplier GM uses in your area to get their entertainment modules repaired you might be able to pull the unit yourself and send it to them for repair. In upstate NY all the dealers send their stuff to United Radio in Syracuse.

Here is their web info if you are interested:

http://unitedradio.com/automotive/ It might be worth calling them and seeing what they might be able to do for you.

Bill

 

John-

Thanks for the info.

Bill and I are looking at different possible problems.
I'm wondering if the Nav isn't being told the car's heading, so it can't rotate the arrow. Bill is thinking that the Nav is getting the heading information but can't process it.

Since you aren't having any other problems with the AH or other systems, that lends a bit credence to the idea of an internal problem in the Nav.

Any other thoughts or information?

 

I'm thinking an internal error because a NAV unit does not really get heading information...it only gets position information. The heading is then generated internally by comparing the current position to the previous position. This is the same way that it calculates speed...by comparing the distance from the previous position to the current position divided by the time span. If a NAV unit is standing still, it does not know which way it is pointed and will just show the direction that it was last moving.

 

I used to believe that also, but...

When I'm in a big underground parking garage where you would not expect to get a GPS signal, and the "No GPS" flag is indeed showing on the factory Nav, it still knows our direction of travel and can approximately calculate our position by Dead Reckoning- speed/time/direction. As I drive 'round and 'round, searching desperately for a parking spot where our doors won't get dinged, the Nav screen shows us doing all the turns.

Also, when I drive up our ~50 yards driveway, the nav shows our proper movement and direction. If I do slight S-turns up the driveway, the system shows them also. If I stop at the street and back down the driveway and do slight turns, the Nav shows everything except it does not reverse our direction, it knows that we are still pointed up toward the street even though we are traveling in the opposite direction.

Based on that, I've come to believe there is some kind of heading input into the Nav, that does not rely on the GPS signal. Whether it is the same heading info that Active Handling uses, or something else, I'm not sure. So I think it leaves the OP's problem open to two possibilities- Nav isn't getting the heading input, or it is getting the heading input but can't process it.

"I don't understand all I know about this stuff."

 

This is a great line.....!! Is it ok if I steal this line from you to use at the appropriate time...??

 

Feel free to use it any time, because it didn't come from me.

Back when I was a young copilot on UAL, the Captain and I were discussing some technical issue about the airplane; he used that line and it stuck with me. I thought it was both funny and profound at the same time, and my opinion hasn't changed over the last 30 years.

I wish I could remember his name, virtually all of those guys were great pilots and great people.

 

Interesting....maybe they have integrated a compass into the NAV unit to show the pointy end of the car. I think a good way to check this would be to back down a street in reverse and see if the arrow turns around and points in the direction of travel or if it stays facing forward...

 

What I was trying to say, is that the triangle keeps pointing forward from the front of the car, even when I back up for ~50 yards. So somehow, the car knows not only what direction we are going, but what direction the front of the car is pointed. Usually the two are identical, but not when backing up. And the Nav somehow knows that.

"I don't understand..."