faze tach illumination not working

[HATCHET_HONDA]

so i bought this 5in faze tach off ebay when i did my d15b swap in the ef.....its been workin great!...well now the damn thing only lights up when i first turn on the headlights, then goes out when the tach needle starts to move..wtf?

 

[INJEN78]

how do you have it wired???
red to________(where does it pull power from)
black to_________(where is it grounded at)
green to______(tach adaptor,wired into factory tach wire or the green wire on the dizzy)
white to_________(whats illuminating it,switch ran to power wire,headlight switch??

 

[HATCHET_HONDA]

mechanicly it works fine..just the backlight goes off and on. i have tested the power wire (which is tapped into the parking light circuit) with a test light and its gettin juice so idk...

 

[INJEN78]

maybe a loose connection in the tach itself..try to return it..tell them it wont light up