AFR gauge not working.

When I put in my new dash I did not hook up the ground to my autometer wideband.
It was un hooked for a few days before I took the dash back out and hooked up the ground. Now with the ground hooked up the gauge won't come on. It's just black, no count down, nothing.

Could I have damaged it by habing the hot hooked up and no ground?

All the wiring is the same as before bit now it won't turn on.
What should I look at to get it back working?

I just put on a new carb so I would very much like to get it working again, not to mention it wasn't cheep and I don't want to buy a replacement....

Thanks again!