Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. See this manual’s Maintenance Schedule
or Index for more information. Things that are especially
important in trailer operation are automatic transmission
uid, engine oil, axle lubricant, belts, cooling system
and brake system. It is a good idea to inspect
these before and during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
The 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 and crew cab pickups have a
seven-wire trailer towing harness.
For vehicles not equipped with heavy duty trailering, the
harness is secured to the vehicle’s frame behind the
spare tire mount. The harness requires the installation of
a trailer connector, which is available through your
dealer/retailer.
If towing a light-duty trailer with a standard four-way
round pin connector, an adapter is available from your
dealer/retailer.
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A.Engine Air Cleaner/Filter on page 5-22.
B. Coolant Surge Tank and Pressure Cap.
SeeCooling System on page 5-30.
C. Positive (+) Terminal. SeeJump Starting on
page 5-46.
D.Battery on page 5-45.
E. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-17.
F. Automatic Transmission Dipstick. See “Checking
the Fluid Level” underAutomatic Transmission Fluid
(4-Speed Transmission) on page 5-24orAutomatic
Transmission Fluid (6-Speed Transmission) on
page 5-27.
G. Remote Negative (−) Terminal (Out of View).
SeeJump Starting on page 5-46.
H. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 5-17.
I. Engine Cooling Fan. SeeCooling System on
page 5-30.
J. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-39.
K. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-41.
L.Underhood Fuse Block on page 5-127.
M. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-40.Engine Oil
For diesel engine vehicles, see “Engine Oil” in the
DURAMAX®Diesel manual.
Checking Engine Oil
It is a good idea to check the engine oil level at each
fuel ll. In order to get an accurate reading, the oil must
be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop.
SeeEngine Compartment Overview on page 5-16
for the location of the engine oil dipstick.
1. Turn off the engine and give the oil several minutes
to drain back into the oil pan. If this is not done,
the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
5-17