Rear Lights not working, any suggestions?

[JrCarr]

I little over a year ago I took the bed off of my truck. I disconnected the rear lights and the truck sat for a while. About 8 months ago I reconnected the lights and everything was backwards. When the light switch was off the rear lights were on. When the light switch was on the rear lights turned off. I disconnected everything and put it on the back burner. Now last night I tried again and now I don't have any lights at all. If anyone can give me suggestions as to troubleshooting this I will appreciate it.