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Discussion Starter #1
I have the MKIII NAV in my 2004 RR, and for the last couple days I've had an odd problem. It seems to have plenty of dots for satellite reception, and it seems to find my location just fine, but the system seems to have no idea which direction I'm facing/traveling. I haven't had a chance yet to go back to the rear door to look at the antenna/cable, but the location seems pretty accurate so I'm not sure that is the issue.

Does anyone know if there is a real electronic compass in these systems or if it relies totally on the GPS? When I bring up compass mode by selecting off road navigation, the compass just spins around wildly while the position indicator stays in the same place (and it appears to be the correct location +/- a few feet although it is hard to judge exactly due to the scale of the map). While using on-road navigation the directions are totally unusable because it keeps thinking I'm going the wrong direction and re-calculating or telling me to make a u-turn.

Any suggestions?
 

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Discussion Starter #2
I found that there is a "secret" service menu in the display. I go to the "set" screen then hold menu until it shows the service menu (about 10 seconds or so). In this mode I can confirm that I do have an accurate location both stationary and while driving. I compared the exact coordinates with a hand held device I have and they were basically identical. Also there is a gyro which determines the compass heading, and it too appears to work perfectly, the readings match up with my hand held device which also has an electronic compass. It also shows that at any given time while I'm driving, I am locked on to 7-8 satellites at all times unless I drive under a bridge or something.

The problem comes when I go back to look at the map/driving directions... the pointer on the map which indicates vehicle position just keeps spinning randomly in all directions and screws up the navigation. What is it getting the direction from if not the compass? The compass headings are always correct in the service menu, but when I go back to the map, they are all screwed up. Could it be software related (and if so why the sudden change, it has worked fine for years)?
 

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UPDATE: I fixed it... not sure exactly what the issue was, but I ejected the CD, waited until the red light went out... then removed the nav unit and unplugged everything. Waited a little while (about 10 minutes) to make sure nothing inside the unit would be holding any capacitance (hopefully)... then I plugged it back in, replaced the unit, started the engine and inserted the map CD.

When it was all done booting up and reading the CD, everything was working normally again. I figured I would post my experience in case anyone else has the same problem.
 

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Discussion Starter #4
On a side note... does anyone have a link to a removal tool which works easily for these NAV units? I managed to get it out with a coat hanger, but it wasn't easy. A proper removal tool doesn't cost much and would make future incidents less time consuming. There are so many different ones which have wildly different shapes online, I can't tell which ones will work the best.
 

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Discussion Starter #5
New Update: It started doing it again.

I still see proper signal, gyro reading, compass heading, etc on the diagnostic screen but the software keeps screwing up when I go to the normal navigation menu. The direction indicator just keeps spinning randomly. I don't get what the problem is. I can fix it by ejecting the CD, waiting about a minute, and then inserting it again. Then all will be normal until the vehicle has been parked for a long time (i.e. several hours), then it will go back to the wacky behavior until I eject the CD again. I know this isn't a battery drain issue or anything, I have a very new battery and the voltage stays strong, around 12.89 volts (which is the same as when I first shut down the engine after driving) even after being parked all weekend.

Could it be that the firmware is somehow corrupted?... seems like if it were, ejecting the CD wouldn't matter... I don't know what it is doing. I don't think there is anything wrong with the hardware because all the diagnostics in the hidden menu look normal, strong signal, correct heading, etc...

Any ideas?
 

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Discussion Starter #7
I don't believe the disk has any issue, it works fine after I eject and re-insert it. Also, the behavior is the same with all the disks in the set (I only tried 3 of them really, but it would be uncanny indeed if all these optical media suddenly failed at the same time). I think it is something to do with the OS on the nav unit, but I really am at a loss to explain why it worked without a single hiccup until recently. I have not attempted firmware flashes or anything. There is no sign of any water leaking in anywhere either and my seal on the rear door looks/feels brand new still.
 

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Discussion Starter #8
Well, I spoke with jhepworth and he helped me find a firmware to try. After some issues with getting my nav computer to recognize the disk which I burned, it is now reporting that it has version 3-1/32 and working normally (again) I'll see if it holds up this time. Hopefully it was just a software problem.
 
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