The calibration procedure for the compass is in the Owner´s manual . My guess is that you don´t have one.
First, is there a line blinking just below the North South markings? is so then you have to find an open space and turn left 360º , two or three turns should do it. That makes the compasss to find the North by itself, After that you still need to compensate for the earth "magnetic deviassions" from your location. That is done by pressing the button ( the only buttond on the compass) continuously for 5 seconds, then a number appears. by pressing the compass button that number changes from 1 to 10, (Saudi Arabia is 7 according to the map on the owners manual) change it to the desire setting and leave it alone, the compass should recalibrate itself.
To recalibrate normaly ( that is if the line was not blinking in the firt place) press the button for 10 seconds and follow the procedures indicated before.
hope my explanation is clear. if not get hold of an owner´s manual, up to 2005 the compass is the same for all models.
Rod