Not sure what I've done wrong, but here's the problem.

I ran some new wire, splicing into a constant source of power from an outlet in my garage. I hooked up an old (2yrs old) security light to it and couldn't get it to run in test mode or come on at all. Didn't really have a volt meter or tester so I just thought it was a shot sensor on the light.
I ran to Home depot and picked up a new security light and an electrical tester. I hooked up the new light, white to white, blk to blk and the copper wire to the ground wire off the light. Same thing, no lights coming on in test mode. I put the tester to it and I have hot wires going to the light. I'm scratching my head on this one and need some input please.

Thanks,
Tony

Sounds correct, but obviously something is wrong. If you have a meter check voltage between

black and white 120VAC
black and ground 120VAC
white and ground 120VAC

If you have that, then your lights are bad.

just to ask, 1) have you fixed this problem?

and 2) if you haven't, I'd just like to know if you're running the wire from the source wire to the light and ending it there, so that the light is constantly on- or if you're trying to add a switch after the light?