2010 Chevrolet Colorado Crew Cab Owner's Manual - Page 155

To calibrate, CAL must be displayed in the mirror compass windows. If CAL is not displayed, press and hold Y b / O for several seconds or until CAL is displayed. The compass can be calibrated by driving the vehicle in circles at 5 mph (8 km/h) or less until the display reads a direction. To adjust for compass variance: 1. Find the current location and variance zone number on the following zone map. Compass Variance The mirror is set to zone eight. If you do not live in zone eight or drive out of the area, the compass variance needs to be changed to the appropriate zone. 2. Press and hold Y number displays. b / O until Z and/or a zone 3. Press Y b / O repeatedly until the new zone number displays. After you stop pressing the button, the display shows a compass direction within a few seconds. 3-41