Brake stop lights issue/Prostar 2009

[kmk]

Recently I have been experiencing intermittent issues with the electrical circuitry for my stop lights, both tractor and trailer. I have replaced the brake switch and the trailer brake lights relay in the panel. Using DLB at the company's shop the brake lights come on. It had inactive code for the load sheedding relay. Are the brake lights connected to it, should I just bypass it? Any suggestions as to what might be the problem, are greatly appreciated.