2002 Altima, how to reset the compass?

The compass in my mirror is not working correctly, it displays only 2 directions, S & SW. It was working great and this happened all of a sudden. The owner's manual is of no help. Can anyone shed some light on how to reset it? Or send me in the right direction, lol?

Thanks, Bob

If there's a button on the front of the mirror, hold it down until "C" or "Cal" appear in the display. Then drive the car slowly in a circle (up to 3 times) until C or Cal dissapear and the direction is correct. If there's no button, look for a small hole on the bottom side of the mirror. Use a paperclip to reset the compass to c or cal as above.

Here are the instructions: http://www.nissanhelp.com/diy/common/nissan_mirror_compass_calibration_procedure.htm