GMC Sierra Limited 1500 2019 Owner's Manual page 315

314 Driving and Operating
Caution
To prevent draining the auxiliary
battery, always turn off electrical
equipment when not in use and
do not use any equipment that
may exceed the
maximum amperage rating of
30 amps.
Trailer Wiring Harness
Basic Trailer Wiring
If the vehicle is not equipped with a
trailer connector on the rear bumper,
a 7-wire trailering harness is tied to
the vehicles frame. The harness
requires the installation of a trailer
connector, which is available
through your dealer.
Use only a round, seven-wire
connector with flat blade terminals
meeting SAE J2863 specifications
for proper electrical connectivity.
The seven-wire harness contains
the following trailer circuits:
Stop/Turn
Yellow/Blue
Signal Left
Stop/Turn
Green/Brown
Signal Right
Tail/Parking
Gray/Brown
Lamps
Reverse Lamps White/Green
Battery Feed Red/Violet
Ground Black
Electric Trailer
Blue
Brake
Heavy-Duty Trailer Wiring Harness
Package
If equipped, the trailer wiring
harness, with a 7-pin connector and
a 4-pin connector, is mounted on
the vehicle's rear bumper.
The trailer connectors contain the
following circuits.
1. Ground
2. Tail Lamps