'95 Ford Escort backup & plate lights

My '95 Escort's backup lights and license plate bulbs are good but none one of them will light. They seem to be coming from the same place too. Anybody have this problem? "ground wire?"

This should be two different circuits. I'd invest in a test probe. That way you can find a good ground and then see if power is going to the light sockets. If there is power then you have a ground problem. If there is no power then it's something else. Could even be two unrelated problems.