I have new two Drawtite harness that plug in and let you install a brake control in the cab.
They are brand new, never opened.
They fit......I have 2 unopened do-it-yourself trailer wiring harnesses that fit:
2003 and up Chevy Avalanche, Silverado, Suburban, and Tahoe
2003 and up GMC Sierra and Yukon (All Models)
2003 and up Cadillac Escalade (All Models)
2003 and up Hummer H2
This is the harness for connecting a brake control to the vehicle
The part number is Drawtite 18264
$10 each OBO
Cash only please