My brake installer told me that you can even reuse one of the old brake magnets wired inline, and that would also resolve the problem.
I had to do this on my 2002 Duramax. Since I had the magnets already installed (DIY cost me $5) I just left them in place with my 2017 Duramax. I don't think they would be needed, but I can say that everything is working.
Without the magnets the integrated controller on my 2002 would not work at all. The magnets "fool" the controller into thinking that the electrical signal is going to the brakes. To test you have to have a tester based on a automobile headlamp. Without it a multimeter will no more receive a signal from the integrated controller than the hydraulic actuator will. I spent hours with a professional disc brake installer who did not know this--and in fact would not believe it.
This relates to the older Duramax not the 2017. I built a tester with a headlamp from a junkyard. When I went to a Chevrolet dealer, he had a very similar tester.