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:

    Empty Folder
    Folders that do not contain files are skipped, and the player advances to the next folder that contains files. ...

    Overheated Engine Protection Operating Mode
    If an overheated engine condition exists and the ENGINE POWER IS REDUCED message displays, an overheat protection mode which alternates firing groups of cylinders helps to prevent engine damage. In th ...

    Overview
    The GMC Sierra All Terrain HD concept is an exploration of heavy-duty truck capability combined with greater off-road versatility. It is highlighted by a bold exterior design, enhanced all-terrain ...