GMC CHEVROLET Silverado 6500HD 2019 Owner's Manual page 261

260 Driving and Operating
vehicle as part of the trailer wiring
package. The harness contains the
following circuits:
Electric Trailer
Blue
Brakes
Red/Black or
Battery Feed
Red/Blue
Brake Apply
White/Blue
Signal
Ground Black
It will be necessary to have a
technician connect the 12-volt
power to the engine compartment
fuse block.
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 0 227.
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 Weight of the Trailer under
Trailer Towing 0 254.
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.