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:
Electrical System Overload
The vehicle has fuses and circuit breakers to protect against an electrical system overload.
When the current electrical load is too heavy, the circuit breaker opens and closes, protecting the circui ...
Running the Vehicle While Parked
It is better not to park with the engine running. But if you ever have to, here are some things to know.
WARNING
Idling a vehicle in an enclosed area with poor ventilation is dangerous. Engine exhau ...
Trailer Towing
If the vehicle has a diesel engine, see the Duramax diesel supplement for more information.
If the vehicle is a hybrid, see the hybrid supplement for more information.
Do not tow a trailer during br ...