1997 GMC Sonoma Owner's Manual - Page 196

When You Are Ready to Leave Parking on aHill * x- - +er Wiring Harness The eight-wire harness is stored under your vehicle along the rear frame crossmember. This harness has a 30-amp feed wire with an inline fuselocated by the junction block. It has no connector and should be wired by a qualified electrical technician. The technician can use the following colorcode chart when connecting the wiring harness to your trailer. Dark Blue: Use for electric trailer brakes or auxiliary wiring. 0 Red: Use for battery charging; it connects to the starter solenoid. 0 Light Green: Back-up lamps. 0 Brown: Taillamps and parking lamps. 0 Yellow: Left stoplamp and turn signal. e Dark Green: Right stoplamp and turn signal. 0 White (Heavy Gage): Ground wire. 0 White (Light Gage): Auxiliary stoplamp. 0 1. Apply your regular brakes and hold the pedal down while you: Start your engine; Shift into a gear; and 0 Release the parking brake. 2. Let up on the brake pedal. 3. Drive slowly until the trailer is clear of the chocks. 4. Stop and have someone pick up and store the chocks. Maintenance When Trailer Towing Your vehicle will need service more often when you're pulling a trailer. See theMaintenance Schedule for more on this. Things that are especially important in trailer operation are automatic transmission fluid (don't overfill), engine oil, axle lubricant, belt, cooling system and brake adjustment. Each of these is covered in this manual, and the Index will help you find them quickly. If you're trailering, it's a good idea to review these sections before you start your trip. Check periodically to see that all hitch nuts and bolts are tight. Securely attach the harnessto the trailer, then tapeor strap it to your vehicle's frame rail. Be sure you leave it loose enough so the wiring doesn't bendor break, but not so loose that it drags on the ground. Storethe harness in its original place. Wrapthe harness together and tie it neatly so it won't be damaged. 4-58