On the dome light, one of the screws that mount it to the roof is the ground, make sure that's clean, might just take a couple slight twists and final tightening to get that working, As for the rest, I'm not sure...
On my '97 dome light, I only put in 2 of the 3 bulbs, those bulbs are BRIGHT when it's dark out, since it turns on all 3 when a door is open... When I got mine it missing most of the dome light, and going through the junk yards that seems to be common, I had to drill some holes and zip tie the reflector to the bracket since the factory fastening was all broken off.