Roger Humphries

I have a 2020 Chevrolet 2500HD, my tail lights & side marker light doesn't work. But everything else works R&L turn signals, brakes lights & brake all work. I have no power on #4 on either plug. The one in the bed is the same as the bumper, no power on #4 tail lights & markers. The is fuse (#41) is good, also put anew in still nothing. Any suggestions?