Page 101 of 412

2-24
4. Before starting the engine, be sure to unplug
and store the cord as it was before to keep it away
from moving engine parts. If you don't, it could
be damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead of
trying to list everything here, we ask that you contact
your dealer in the area where you'll be parking your
vehicle. The dealer can give you the best advice for
that particular area.Automatic Transmission Operation
There are several different positions for your shift lever.
Your vehicle is equipped with an automatic
transmission, and it features an electronic shift position
indicator within the instrument cluster. This display
must be powered anytime the shift lever is capable of
being moved out of the PARK (P) position. This means
that if your key is in OFF, but not locked, there will be a
small current drain on your battery which could
discharge your battery over a period of time. If you have
a need to leave your key in the ignition in OFF for an
extended period for any reason, it is recommended that
you disconnect the battery cable from the battery to
prevent discharging your battery.
Page 233 of 412

4-41 Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If you don't shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude on
steep uphill grades, your vehicle may show signs similar to
engine overheating. To avoid this, let the engine run while
parked (preferably on level ground) with the automatic
transmission in PARK (P) for a few minutes before turning
the engine off. If you do get the overheat warning, see
ªEngine Overheatingº in the Index.
Parking on Hills
CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People can
be injured, and both your vehicle and the trailer
can be damaged.
But if you ever have to park your rig on a hill, here's
how to do it:
1. Apply your regular brakes, but don't shift into
PARK (P) yet. Then turn your wheels into the curb if
facing downhill or into traffic if facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your parking
brake and then shift to PARK (P).
5. Release the regular brakes.
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.
Page 234 of 412

4-42 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, 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
The optional heavy-duty trailer wiring package is a
seven
-wire harness assembly. The four-wire portion of
the harness assembly is stored under the vehicle, along
the driver's side rear corner of the frame rail. The
three
-wire portion of the harness assembly is stored in a
frame pocket under the rear of the vehicle, on the
driver's side. The heavy
-duty trailer wiring harness has
a 30
-amp feed wire. Both harnesses come without
connectors and should be wired by a qualified electrical
technician. The technician can use the following color
code chart when connecting the wiring harness to
your trailer.Four
-Wire Harness
Light Green: Back
-up lamps
Brown: Parking lamps
Yellow: Left stoplamp and turn signal
Dark Green: Right stoplamp and turn signal
Three
-Wire Harness
Dark Blue: Use for electric trailer brakes
(seven
-wire harness only)
Orange: Trailer accessory (seven
-wire harness only)
White (heavy gage): Ground wire
Securely attach the harness to the trailer, then tape or
strap it to your vehicle's frame rail. Be sure you leave it
loose enough so the wiring doesn't bend or break, but
not so loose that it drags on the ground. Store the
harness in its original place. Wrap the harness together
and tie it neatly so it won't be damaged.
Page 270 of 412

6-
6-1
Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-3 Fuel (Gasoline Engine)
6
-5 Fuels in Foreign Countries (Gasoline Engines)
6
-5 Filling Your Tank (Gasoline Engine)
6
-7 Filling a Portable Fuel Container
6
-8 Checking Things Under the Hood
6
-11 Noise Control System
6
-12 Engine Oil (Gasoline Engine)
6
-16 Engine Air Cleaner/Filter (Gasoline Engines)
6
-18 Automatic Transmission Fluid
6
-22 Rear Axle
6
-22 Engine Coolant
6
-26 Radiator Pressure Cap
6
-26 Power Steering Fluid
6
-27 Windshield Washer Fluid
6
-28 Brakes
6
-32 Battery6
-33 Bulb Replacement
6
-40 Windshield Wiper Blade Replacement
6
-41 Tires
6
-50 Appearance Care
6
-51 Cleaning the Inside of Your Vehicle
6
-54 Cleaning the Outside of Your Vehicle
6
-56 Cleaning Aluminum Wheels (If Equipped)
6
-56 Cleaning Tires
6
-56 Sheet Metal Damage
6
-57 Finish Damage
6
-58 GM Vehicle Care/Appearance Materials
6
-59 Vehicle Identification Number (VIN)
6
-60 Electrical System
6
-66 Replacement Bulbs
6
-67 Capacities and Specifications
6
-70 Normal Maintenance Replacement Parts
Page 279 of 412
6-10 Engine Compartment Overview
When you lift the hood, you'll see these items:
A. Battery
B. Coolant Recovery Tank
C. Engine Oil DipstickD. Engine Oil Fill
E. Transmission Dipstick
F. Engine Air Cleaner/FilterG. Power Steering Reservoir
H. Brake Master Cylinder
I. Windshield Washer Fluid
Page 287 of 412

6-18
CAUTION:
Operating the engine with the air cleaner/filter
off can cause you or others to be burned. The air
cleaner not only cleans the air, it stops flame if
the engine backfires. If it isn't there, and the
engine backfires, you could be burned. Don't
drive with it off, and be careful working on the
engine with the air cleaner/filter off.
NOTICE:
If the air cleaner/filter is off, a backfire can
cause a damaging engine fire. And, dirt can
easily get into your engine, which will damage it.
Always have the air cleaner/filter in place when
you're driving.
Automatic Transmission Fluid
If your vehicle has a diesel engine, see ªAutomatic
Transmission Fluidº in the Diesel Supplement.
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 50,000 miles
(83 000 km) if the vehicle's GVWR is over 8,600 or
if the vehicle is mainly driven under one or more of
these conditions:
In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery service.
If your vehicle's GVWR is not over 8,600 and you do not
use your vehicle under any of these conditions, change the
fluid and filter every 100,000 miles (166 000 km).
See ªScheduled Maintenance Servicesº in the Index.
Page 359 of 412

Short Trip/City Scheduled Maintenance
7-20
48,000 Miles (80 000 km)
Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)
Check axle fluid level and add fluid as needed. (See footnote **.)
Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)
Diesel Engine Only: Replace fuel filler cap if driving in dusty conditions.
An Emission Control Service.
50,000 Miles (83 000 km)
Change automatic transmission fluid and filter if the vehicle has a diesel
engine, if the vehicle's GVWR is over 8600 lbs. or if the vehicle is mainly
driven under one or more of these conditions:
± In heavy city traffic where the outside temperature regularly reaches
90F (32C) or higher.
± In hilly or mountainous terrain.
± When doing frequent trailer towing.
± Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these conditions, change the fluid
and filter at 100,000 miles (166 000 km).
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE
Page 370 of 412

Short Trip/City Scheduled Maintenance
7-31
99,000 Miles (165 000 km)
Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)
Check axle fluid level and add fluid as needed. (See footnote **.)
100,000 Miles (166 000 km)
Gasoline Engine Only: Inspect spark plug wires.
An Emission Control Service.
Gasoline Engine Only: Replace spark plugs.
An Emission Control Service.
Change automatic transmission fluid and filter if the vehicle has a diesel
engine, if the vehicle's GVWR is over 8600 lbs. or if the vehicle is mainly
driven under one or more of these conditions:
± In heavy city traffic where the outside temperature regularly reaches
90F (32C) or higher.
± In hilly or mountainous terrain.
± When doing frequent trailer towing.
± Uses such as found in taxi, police or delivery service.
(Continued)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE