GMC Sierra 2014 Owner's Manual page 356

9-92 Driving and Operating
The harness contains the following
camper/trailer circuits:
Green/Violet: Left Stop/Turn
Signal
Yellow/Gray: Right Stop/Turn
Signal
Gray/Brown: Taillamps/
Parklamps
White: Ground
White/Green: Back-up Lamps
Red/Green: Battery Feed
Dark Blue: Trailer Brake
If the vehicle is equipped with the
heavy-duty trailering option, see
Heavy-Duty Trailer Wiring Harness
Package earlier in this section.
When the camper-wiring harness is
ordered without the heavy-duty
trailering package, a seven-wire
harness with a seven-pin connector
is at the rear of the vehicle and is
tied to the vehicle's frame.
Electric Brake Control Wiring
Provisions
These wiring provisions are
included with the vehicle as part of
the trailer wiring package. These
provisions are for an electric brake
controller.
The harness should be installed by
your dealer or a qualified service
center.
Tow/Haul Mode
Pressing this button at the end of
the shift lever turns on and off the
Tow/Haul Mode.
This indicator light on the instrument
cluster comes on when the Tow/
Haul Mode is on.
Tow/Haul is a feature that assists
when pulling a heavy trailer or a
large or heavy load. See Tow/Haul
Mode on page 9-38.