Park Assist - Power, Ground, Serial Data and Control (UD7 or UD5)

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2015 GMC Sierra 3500 HD, 2015 GMC Sierra 2500 HD, 2015 GMC Sierra 1500, 2015 Chevrolet Silverado 3500 HD, and 2015 Chevrolet Silverado 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.