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The Corvette owner's manual indicates that if the compass in the mirror is not adjusted for compass variance, the compass could give false readings. It further states that the mirror is set in zone eight upon leaving the factory and that it will be necessary to adjust the compass to compensate for compass variance if you live outside of zone eight. To adjust for compass variance, you need to press and hold the left map light button until a zone number appears on the display and then press the on/off button quickly until you reach the correct zone number. When I press and hold the button as instructed, nothing happens. Anyone else have this problem?
You are doing this attempt at setting the compass variance with the engine running, right? At the very least, you should either get a zone number or the letter "C" when you hold in the light button.
Are you getting a direction indication from the compass at all, before you try to set the variance?
Just tried to change the compass variance in my C6 with auto tranny. Like yours, it would not do anything at all when I pressed and held the left map light (while the engine was running).
Note the 2nd paragraph on page 2-35. Maybe you could try driving the vehicle in circles at 5 MPH or less for a minute or two to see if that helps.
Just a note, the dealer is paid to calibrate the compass for the region the dealer is in during PDI.
As for when you are driving cross-country, it is hard to notice a difference in the calibration from zone to zone. Comparing my Jeep compass (same company makes the Jeep and GM mirror/compass/dimming mirrors) with my Magellan GPS compass after traveling between three different zones, showed that I was eight degrees off.
Yes, my attempts at calibration have been done with the car running but to no avail. As you indicate, it may have already been done at the dealership and perhaps the difference from zone to zone is so small that it wouldn't make much of a difference anyway. Even so, I can't help wondering why following the instructions in the owner's manual doesn't do what it says it should.
Last edited by timbo1; Jan 5, 2005 at 02:43 PM.
Reason: spelling
Here is a website that shows you the Magnetic Variation for any location by long/lat or you can just run your cursor over any part of the world to see what it is.
For instance on the east coast (Mid-Atlantic) it is about 7-8 degs off and goes down 0 around Georga and then up to 15 degs or so out on the west coast (Washington).
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The reading on my compass was off on the drive home from the dealer. Before I could attempt recalibrating it, I began to get correct readings. This was after a few days of routine driving. (?).