GMC Yukon 2021 Owner's Manual page 293

292 Driving and Operating
Green/Violet: Right Stop/Turn Signal
Grey/Brown: Taillamps
White: Ground
White/Green: Back-up Lamps
Red/Green: Battery Feed
Dark Blue: Trailer Brake
To help charge a remote (non-vehicle)
battery change drive mode to Tow Haul.
If the trailer is too light for Tow/Haul Mode,
turn on the headlamps to help charge the
battery.
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.
Refer to the aftermarket electric trailer brake
controller owner's manual to determine wire
color coding of the electric trailer brake
controller. The wire colors on the brake
controller may be different from the vehicle.
Trailer Lamps
Always check all trailer lamps are working at
the beginning of each trip, and periodically
on longer trips.
Turn Signals When Towing a Trailer
When properly connected, the trailer turn
signals should will illuminate to indicate the
vehicle is turning, changing lanes,
or stopping. When towing a trailer, the
arrows on the instrument cluster will
illuminate even if the trailer is not properly
connected or the bulbs are burned out.
Tow/Haul Mode
For instructions on how to enter Tow/Haul
mode, see Tow/Haul Mode 0 235.
Tow/Haul assists when pulling a heavy
trailer or a large or heavy load.
Tow/Haul Mode is designed to be most
effective when the vehicle and trailer
combined weight is at least 75% of the
vehicle's Gross Combined Weight Rating
(GCWR). See Maximum Trailer Weight
under Trailer Towing 0 284.
Tow/Haul Mode is most useful when towing
a heavy trailer or carrying a large or
heavy load:
through rolling terrain
in stop-and-go traffic
in busy parking lots
Operating the vehicle in Tow/Haul Mode
when lightly loaded or not towing will not
cause damage; however, it is not
recommended and may result in unpleasant
engine and transmission driving
characteristics and reduced fuel economy.
Integrated Trailer Brake Control System
The vehicle may have an Integrated Trailer
Brake Control (ITBC) system for use with
electric trailer brakes or most electric over
hydraulic trailer brake systems. These
instructions apply to both types of electric
trailer brakes.
This symbol is on the Trailer Brake Control
Panel on vehicles with an ITBC system. The
power output to the trailer brakes is
proportional to the amount of vehicle