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GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 2/11/15
Driving and Operating
9-81
Basic Trailer Wiring
All regular, double cab, and crew
cab pickups have a seven-wire
trailer towing harness.
For vehicles not equipped with
heavy-duty trailering, the harness is
secured to the vehicle's frame
behind the spare tire mount. The
harness requires the installation of a
trailer connector, which is available
through your dealer.
Heavy-Duty Trailer Wiring Harness
Package
For vehicles equipped with
heavy-duty trailering, the harness
connector is mounted in the bumper.
The seven-wire harness contains
the following trailer circuits:
.
Green/Violet: Left Stop/Turn
Signal
.
Yellow/Gray: Right Stop/Turn
Signal
.
Gray/Brown: Taillamps/Parking
Lamps
.
White: Ground
.
White/Green: Back-up Lamps
.
Red/Green: Battery Feed
.
Dark Blue: Trailer Brake
If charging a remote (non-vehicle)
battery, press the Tow/Haul Mode
button, if equipped, 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.
Camper/Fifth-Wheel Trailer Wiring
Package
The seven-wire camper harness is
under the rear bumper, attached to
the frame near the rear
crossmember. A connector must be
added to the wiring harness that
connects to the camper.
The harness contains the following
camper/trailer circuits:
.
Green/Violet: Left Stop/Turn
Signal
.
Yellow/Gray: Right Stop/Turn
Signal
.
Gray/Brown: Taillamps/Parking
Lamps
.
White: Ground
.
White/Green: Back-up Lamps
.
Red/Green: Battery Feed
.
Dark Blue: Trailer Brake