Kenworth t800 light issues

Working on a 2013 T800 that has no right break or turn light, and when the high beams are on both left headlights go out. I chase the wires up to the box above the drive shaft and still found no power for right turn or break. Though all of the trailer break and turn lights work. I’m suspicious of the turn signal controller on the steering column but I’m unsure. Anyone of any thoughts