Check your manual. There is a way to adjust the brightness of your speedo. I've done it before but can't remember how. I think you hold down the select button for like five seconds or something like that.
Found it.
For those who didnt know:
turn key off
hold /\ side of the select switch
turn key on
keep holding /\ for 5+ secs
then press /\ \/ to select brightness
push reset to confirm choice