2010 Hummer H3 Owner's Manual - Page 263

Driving and Operating Safety Chains Always attach chains between the vehicle and the trailer. Cross the safety chains under the tongue of the trailer to help prevent the tongue from contacting the road if it becomes separated from the hitch. Always leave just enough slack so the rig can turn. Never allow safety chains to drag on the ground. 9-79 Trailer Wiring Harness Light‐Duty Trailer Wiring Package If the vehicle does not have a trailer towing package, the chassis harness will contain the following blunt cut circuits: . . Heavy-Duty Trailer Wiring Package Yellow: Left Stop/Turn Signal Dark Green: Right Stop/Turn Signal White: Ground Brown: Tail Lamps If the vehicle has a trailer towing package, the rear bumper harness will have a seven‐pin universal heavy‐duty trailer connector attached to a bracket on the hitch platform. Trailer Brakes A loaded trailer that weighs more than 680 kg (1,500 lbs) needs to have its own brake system that is adequate for the weight of the trailer. Be sure to read and follow the instructions for the trailer brakes so they are installed, adjusted and maintained properly. . . To add a trailer towing wiring package, have it installed by your dealer or a qualified service center. Also, see Add-On Electrical Equipment on page 9‑81 for more information.