VNL LCM issues no bad fuses

I have a 2005 vnl 430. Have an issue with not having the trailer brake lights and left turn signal. As well as no dash indicators for flashers but works on the outside and turn signals on truck work normally. When I start the truck I get codes check fuse lcm 3. I have double triple checked all obvious grounds and battery connections. Swapped lcm from our other truck with no change but says headlights are out, im sure from different programming. All fuses test good and swapped relays with no change. I even used some jumper cables to go from negative battery terminal to firewall ground and to engine.