Yes, I just bought a 2020 Sierra SLT. When I hook up the trailer and connect the 7-pin adapter to 4 blade wiring harness, no lights, and the Infotainment System shows "No Trailer Detected". Of course, the dealership is completely oblivious of this and want me to bring the truck in to the service department. This should not be the procedure. That is a waste of my time. A little background on this situation, I just bought a boat and thought maybe it was the trailer lights or the wiring harness but none of the lights work on the trailer once hooked up to the truck. So I hooked up my 2001 Tahoe to the boat trailer and all the lights work.