I had the same "trailer disconnect" alert while connected to my all LED lights trailer. Thinking the LED's don't draw as much power and the system on my 2019 Sierra SLT won't recognize. I purchased from Amazon a Tow Ready 20142 7-Way Flat Pin to 7-Flat Adapter, which is made for European vehicles, and it solved the "trailer disconnect" problem. Adapter price is currently around $22. Hope this helps.