Clock/Ambient Temp won't light up

[dcollin]

I replaced my ambient temp/clock with a new one-new used-and it works good but won't light up. The bulbs appear to be fine. I have some extra's and i switched them around-nothing. All my other dash lights work, except the rear window defroster isn't working. All fuses are good. Any thoughts?
Thanks

[BahnE30]

how does it work good if it won't lite up, i'm assuming you mean the back light, if so chances are it's burnt out, sol afaik