I have a 2017 Colorado I just bought used. The trailer running lights are not working. The turn signals, brakes and hazards all work. I rewired the trailer and tested on another truck and it works. I also tested with the pin tester (four pin which is how I connected it) and one of them do not light up. I have checked the fuses and they are all good. We also tested the pin tester on another truck and they all lit up fine. Any suggestions?