how to wire this rev counter

[dan23]

http://img73.imageshack.us/img73/6144/image268lj4.th.jpg (http://img73.imageshack.us/my.php?image=image268lj4.jpg)

http://img73.imageshack.us/img73/8646/image266dz1.th.jpg (http://img73.imageshack.us/my.php?image=image266dz1.jpg)

there are 4 wires
black
green
brown
grey

[dan23]

i am guessing
black is igntion live
brown
earth
green to coil

but what about the grey one ?

[Lee]

It will be for the backlight at a guess. Wire it to the grey/green wire that runs to the dash :)

[djshaggeh]

Grey might need wring to the light switch, assuming the rev counter has a back light.