Trailer Wiring Harness; Maintenance When Trailer Towing - GMC 2004 Sierra 1500 Pickup Owner's Manual

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
•
Start your engine
•
Shift into a gear
•
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 Scheduled Maintenance on
page 6-4 for more information. Things that are especially
important in trailer operation are automatic transmission
fluid (don't overfill), engine oil, axle lubricant, belt,
cooling system and brake system. 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.

Trailer Wiring Harness

Your vehicle is equipped with one of the following wiring
harnesses for towing a trailer or hauling a slide-in
camper.
Basic Trailer Wiring
All regular, extended cab crew cab pickups have a
six-wire trailer towing harness.
The six-wire harness is located at the rear of the vehicle
and is tied to the vehicle's frame. The harness requires
the installation of a trailer-wiring harness connector,
which is available through your dealer.
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