2010 GMC Sierra 1500 Crew Cab Owner's Manual - Page 447

When trailering, make sure of the following: { WARNING: Connecting a trailer that is not compatible with the ITBC system may result in reduced or complete loss of trailer braking. There may be an increase in stopping distance or trailer instability which could result in personal injury or damage to the vehicle, trailer, or other property. An aftermarket controller may be available for use with trailers with surge, air or electric‐over‐hydraulic trailer brake systems. To determine the type of brakes on the trailer and the availability of controllers, check with your trailer manufacturer or dealer. . The ITBC system is used only with trailers that are equipped with electric brakes. All applicable local and federal laws and regulations are followed. All electrical and mechanical connections to the trailer are made correctly. The trailer's brakes are in proper working condition. The trailer and vehicle are properly loaded for the towing condition. . . . . The ITBC system is a factory installed item. Out‐of‐factory installation of this system should not be attempted. GM is not responsible for warranty or performance of the system resulting from out‐of‐factory installation. 5-71