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:

    Shutting the Engine Off After a Remote Start
    To shut off the engine: ○ Press until the parking lamps turn off. ○ Turn on the hazard warning flashers. ○ Insert the key and turn it to ON/ RUN and then back to LOCK/OFF. ...

    Place a Call Using a Stored Number
    1. Push . System responds: “OnStar ready.” 2. Say “Call <name tag>.” System responds: “OK, calling <name tag>.” ...

    Trip/Fuel Menu Items
    Press the MENU button until Trip/ Fuel Information Menu is displayed. Then press to scroll through the following menu items: ○ Trip 1 ○ Trip 2 ○ Fuel Range ○ Average Fu ...