Trailer Wiring Harness; Maintenance When Trailer Towing - GMC 2008 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, and
•
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 the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission fluid (don't overfill),
engine oil, axle lubricant, belts, 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

For vehicles equipped with heavy duty trailering, the
harness is connected to a bracket on the hitch platform.
The seven-wire harness contains the following trailer
circuits:
•
Yellow: Left Stop/Turn Signal
•
Dark Green: Right Stop/Turn Signal
•
Brown: Taillamps
•
White: Ground
•
Light Green: Back-up Lamps
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