1998 Oldsmobile Bravada Gauge Cluster

I bought my son his first vehicle, a 98 Bravada. We've had it less than a week and so far the major problem we have come across is the lights in for the gauge cluster in the dash are not coming on. First I thought it was a blown bulb so we replaced that. When we were putting the dash back together, I turned the truck on and turned on the headlights and got nothing. So I jiggled some wires thinking that it might've been a short or a loose wire and still nothing. It was getting dark so my son decided to put everything back together and try again in the morning. When he reconnected the connector for the dome/fog light, everything came back on. But when he moved the dashboard to put it back in place, everything went back out again. Again, I jiggled wires and nothing, not even a flicker. Now there's no lights in the dash and when he turns on the headlights, the radio lights go out along with the compass/MPG gauge located overhead. Any ideas as to what the problem might be?