GMC 2010 Sierra Owner's Manual page 458

*The fuses for these two circuits are installed in the
underhood electrical center, but the wires are not
connected. They should be connected by your dealer or
a qualified service center. The fuse and wire for the
ITBC is factory installed and connected if the vehicle is
equipped with an ITBC. The fuse for the battery feed is
not required if the vehicle has an auxiliary battery. If the
vehicle does not have an auxiliary battery, have your
dealer or authorized service center install the
required fuse.
If charging a remote (non-vehicle) battery, press the
Tow/Haul mode button, if equipped, located at the end
of the shift lever. This will boost the vehicle system
voltage and properly charge the battery. If the trailer is
too light for Tow/Haul mode, or the vehicle is not
equipped with Tow/Haul, turn on the headlamps as a
second way to boost the vehicle system and charge the
battery.
5-82
Camper/Fifth-Wheel Trailer Wiring Package
The seven-wire camper harness is located under the
front edge of the pickup box on the drivers side of the
vehicle, attached to the frame bracket. A connector
must be added to the wiring harness which connects to
the camper.
The harness contains the following camper/trailer
circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Red: Battery Feed
Dark Blue: Trailer Brake