Volvo 2008 C30 Owner's Manual page 65

Night position
To reduce glare from the headlights of following vehicles, use control (1) to switch between the normal and night-driving
positions.
2. Normal position
3. Night position, reduces glare from following traffic
Auto-dim function (option)
An optional integrated sensor reacts to headlights from following traffic and automatically reduces glare.
Rearview mirror with compass (option)
The upper right-hand corner of the rearview mirror has an integrated display that shows the compass direction toward
which the vehicle is pointing. Eight different directions can be displayed: N, NE, E, SE, S, SW, W and NW. The display
shows your car's orientation with respect to true north.
Calibrating the compass