Compass (ISRVM)
WARNING: This page is about a different car, the 2008 Suzuki XL7. However, it is still accessible from the selected car via links, so may be relevant.
The inside rear view mirror (ISRVM) uses two magnetic field sensors for compass direction. One sensor is for the north and south, the other is for east and west. The ISRVM provides a signal and a low reference to each sensor. As the vehicle travels with or against the earth's magnetic pull, there is a change in voltage on one or both sensors. As a result of the change in voltage, the mirror changes the heading on the compass display. For the compass variance and calibration information refer to COMPASS CALIBRATION AND MAGNETIC VARIANCE (DIC) or COMPASS CALIBRATION AND MAGNETIC VARIANCE (ISRVM) .