NeaLia 7 Pin Trailer Wiring Harness Replacement USCAR, OEM Style Wire Harness for Truck, 7 Way Towing Hitch Socket Connector for Automotive Ford, GM, Chevy, Silverado, GMC, Sierra, Dodge, Ram

Are you actually going to be using the electric brakes/12 volts/reverse signal that the 7-way provides, or just the lights that 4 flat provides, because you can definitely make that work. I'll find and link the plug you'd need to splice on which would connect to that combo plug you want. Just gotta get to my computer. *edit, anything that looks like this will plug into that combo plug, you'll just have to snip the flat off and splice this on after you're done with the wiring install, then it plugs right in. https://www.amazon.com/NeaLia-Replacement-Connector-Automotive-Silverado/dp/B0DZH3R7WN