2008 GMC Sierra 1500 Pickup Owner's Manual - Page 312

• Red: Battery Feed* • Dark Blue: Trailer Brake* *The fuses for these two circuits are installed in the underhood electrical center, but the wires are not connected. They should be connected by your dealer/retailer or a qualified service center. The fuse for the battery feed is not required if your vehicle has an auxiliary battery. If your vehicle does not have an auxiliary battery, have your dealer/retailer or authorized service center install the required fuse. If you are charging a remote (non-vehicle) battery, press the tow/haul mode button located at the end of the shift lever. This will boost the vehicle system voltage and properly charge the battery. If the trailer is too light for tow/haul mode, you can turn on the headlamps as a second way to boost the vehicle system and charge the battery. The harness contains the following wires: • Dark Blue: Brake Signal to Trailer Connector • Red/Black: Battery • Light Blue/White: Brake Switch • White: Ground It should be installed by your dealer/retailer or a qualified service center. Trailer Recommendations You must subtract your hitch loads from the CWR for your vehicle. Weigh your vehicle with the trailer attached, so that you won't go over the GVWR or GAWR. If you are using a weight-distributing hitch, weigh the vehicle without the spring bars in place. You'll get the best performance if you spread out the weight of your load the right way, and if you choose the correct hitch and trailer brakes. For more information, see Towing a Trailer on page 4-41. Electric Brake Control Wiring Provisions These wiring provisions are included with your vehicle as part of the trailer wiring package. These provisions are for an electric brake controller. The instrument panel contains blunt cut wires near the data link connector for the trailer brake controller. 4-54