1998 GMC Yukon Owner's Manual - Page 249

This harness has a 30 amp battery feed wire and no connector, and should be wired by a qualified electrical technician. After choosing an aftermarket mating connector pair, have the technician attach one connector to the eight-wire trailer harness and the other connector to the wiring harness on the trailer. Be sure that the wiring harness on the trailer is strapped to the trailer's frame and leave it loose enough so that the wiring doesn't bend or break, but not so loose that it drags on the ground. The technician can use the following color code chart when connecting the wiring harness to your trailer. 0 Brown: Rear Lamps Yellow: Left Stoplamp and Turn Signal Dark Green: Right Stoplamp and TLUII Signal White (Heavy Gauge): Ground Light Green: Back-up Lamps White (Light Gauge): Center High-Mounted Stop Lamp Blue: Auxiliary/Electric Trailer Brake Circuit Orange: Fused Auxiliary Circuit Additional Heavy-Duty Wiring A eight-wire harness is stored under the rear end of your vehicle. The five-wire light-duty harness is located at the left hand rear inner lower quarter panel. The additional heavy-duty wiring is located forward of the rear bumper and is attached to the center of the rear crossmember or the forward vertical surface of the platform hitch (if equipped). 0 0 0 Store the harness i n its original place. Wrap the harness together and tie it neatly so it won't be damaged. 4-57