Trailer Wiring Harness
Basic Trailer Wiring
The trailer wiring harness, with a seven-pin connector, is located at the rear of the vehicle and is tied to the vehicle's frame. The harness connector can be plugged into a seven-pin universal heavy-duty trailer connector available through your dealer.
The seven-wire harness contains the following trailer circuits:
• Yellow: Left Stop/Turn Signal
• Dark Green: Right Stop/Turn Signal
• Brown: Taillamps
• Black: Ground
• Light Green: Back-up Lamps
• Red/Black: Battery Feed
• Dark Blue: Trailer Brake*
*The fuse for this circuit is installed in the underhood electrical center, but the wires are not connected.
They should be connected by your dealer or a qualified service center.
If the back-up lamp circuit is not functional, contact your dealer.
If a remote (non-vehicle) battery is being charged, press the Tow/Haul mode switch located on the center console near the climate controls.
This will boost the vehicle system voltage and properly charge the battery. If the trailer is too light for Tow/Haul mode, turn on the headlamps (non-HID only) as a second way to boost the vehicle system and charge the battery.
See also:
Initial Drive Information
This section provides a brief overview about some of the important features that
may or may not be on your specific vehicle. For more detailed information, refer
to each of the features which can ...
Parking Brake
To set the parking brake, hold the regular brake pedal down, then push the parking
brake pedal down.
If the ignition is on, the brake system warning light will come on. See Brake
System Warning ...
Fuel
For diesel engine vehicles, see “Fuel for Diesel Engines” in the Duramax Diesel Supplement.
For Vehicles with gasoline engines, please read this. ...





