2001 GMC SIERRA instrument panel

4-58

Then, during the first 500 miles (800 km) that you
tow a trailer, don't drive over 50 mph (80 km/h) and
don't make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at the
heavier loads.

If you have an automatic transmission, you can
tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or, if necessary, a lower
gear selection if the transmission shifts too often
(e.g., under heavy loads and/or hilly conditions).
If you have a manual transmission and you are
towing a trailer, it's better not to use FIFTH (5)
gear. Just drive in FOURTH (4) gear (or, as you
need to, a lower gear). See ªTow/Haul Modeº
in the Index.
Three important considerations have to do with weight:

the weight of the trailer,

the weight of the trailer tongue

and the weight on your vehicle's tires.Tow/Haul Mode (If Equipped)
Tow/haul is a feature on automatic transmission
equipped vehicles that assists when pulling a heavy
trailer or a large or heavy load. The purpose of the
tow/haul mode is to:

Reduce the frequency and improve the predictability
of transmission shifts when pulling a heavy trailer
or a large or heavy load.

Provide the same solid shift feel when pulling a
heavy trailer or a large or heavy load as when the
vehicle is unloaded.

Improve control of vehicle speed while requiring
less throttle pedal activity when pulling a heavy
trailer or a large or heavy load.
Automatic transmission equipped vehicles are provided
with a button at the end of the shift lever which when
pressed enables tow/haul. When the button is pressed,
a light on the instrument panel will illuminate to indicate
that tow/haul has been selected. Tow/haul may be turned
off by pressing the button again, at which time the
indicator light on the instrument panel will turn off.
The vehicle will automatically turn off tow/haul every
time it is started.

4-75 Turn Signals When Towing a Trailer
The arrows on your instrument panel will flash
whenever you signal a turn or lane change. Properly
hooked up, the trailer lamps will also flash, telling other
drivers you're about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will flash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind you
are seeing your signal when they are not. It's important
to check occasionally to be sure the trailer bulbs are
still working.
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.
If you have an automatic transmission, you can tow in
DRIVE (D). You may want to shift the transmission
to THIRD (3) or, if necessary, a lower gear selection if
the transmission shifts too often (e.g., under heavy loads
and/or hilly conditions).You may also want to activate the tow/haul mode if the
transmission shifts too often. See ªTow/Haul Modeº in
the Index.
If you have a 5
-speed manual transmission and you are
towing a trailer, it's better not to use FIFTH (5) gear.
Just drive in FOURTH (4) gear (or, as you need to,
a lower gear).
If you have a 6
-speed manual transmission and you
are towing a trailer, it's better not to use SIXTH (6)
gear. Drive in FIFTH (5) gear (or, as you need to,
a lower gear).
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) (or the
manual transmission out of gear and the parking brake
applied) for a few minutes before turning the engine off.
If you do get the overheat warning, see ªEngine
Overheatingº in the Index.

4-79
The eight-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

Light Blue: CHMSL

Red: Battery Feed

Dark Blue: Trailer Brake
A jumper harness for an electric trailer brake controller
and a trailer battery feed fuse are included with this
trailering package. (See ªInstrument Panel Jumper
Wiring Harnessº later in this section.)
If you need to tow a light
-duty trailer with a standard
four
-way round pin connector, an adapter connector is
available from your dealer.Camper/Fifth
-Wheel Trailer Wiring Package
(If Equipped)
The eight
-wire camper harness is located under the
front edge of the pickup box on the driver's side of the
vehicle, attached to the frame bracket. A connector will
have to be added to the wiring harness which connects
to the camper.
The eight
-wire harness contains the following
camper/trailer circuits:

Yellow: Left Stop/Turn Signal

Dark Green: Right Stop/Turn Signal

Brown: Taillamps

White: Ground

Light Green: Back
-up Lamps

Light Blue: Center High
-Mounted
Stoplamp (CHMSL)

Red: Battery Feed

Dark Blue: Trailer Brake
A jumper harness for an electric trailer brake controller
and a trailer battery feed fuse are included with this
trailering package. (See ªInstrument Panel Jumper
Wiring Harnessº later in this section.)

4-80
If your vehicle is equipped with the ªHeavy-Duty
Traileringº option, please refer to ªHeavy
-Duty Trailer
Wiring Packageº, earlier in this section.
When the camper
-wiring harness is ordered without the
heavy
-duty trailering package, an eight-wire harness
with a seven
-pin connector and separate CHMSL
connector are located at the rear of the vehicle and are
tied to the vehicle's frame.Instrument Panel Jumper Wiring Harness
This harness is included with the heavy-duty and
camper/fifth
-wheel trailer wiring packages. The harness
is for an electric trailer brake controller and includes a
trailer battery feed fuse. This harness and fuse should be
installed by your dealer or a qualified service center.

5-8
1. Disconnect the black negative (-) cable from the
heavy, unpainted metal engine part on the vehicle
that had the dead battery.
2. Disconnect the black negative (
-) cable from the
negative (
-) terminal on the vehicle with the
good battery.
3. Disconnect the red positive (+) cable from the
vehicle with the good battery.
4. Disconnect the red positive (+) cable from the
other vehicle.
Towing Your Vehicle
Consult your dealer or a professional towing service if
you need to have your vehicle towed. See ªRoadside
Assistanceº in the Index.
Engine Overheating
You will find a coolant temperature gage on your
vehicle's instrument panel. See ªEngine Coolant
Temperature Gageº in the Index. In addition,
you will find a LOW COOLANT, CHECK COOLANT
TEMP, ENGINE OVERHEATED and a REDUCED
ENGINE POWER message in the message center on the
instrument panel. See ªMessage Centerº in the Index.
Overheated Engine Protection Operating
Mode (V8 Engines Only)
Should an overheated engine condition exist and the
REDUCED ENGINE POWER message is displayed,
an overheat protection mode which alternates firing
groups of cylinders helps prevent engine damage.
In this mode, you will notice a loss in power and
engine performance. This operating mode allows your
vehicle to be driven to a safe place in an emergency.
Towing a trailer in the overheat protection mode
should be avoided.
NOTICE:
After driving in the overheated engine protection
operating mode, to avoid engine damage, allow
the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair
the cause of coolant loss, change the oil and reset
the oil life monitor. See ªEngine Oilº in the Index.

6-4
In Canada, look for the
ªAuto Makers' Choiceº
label on the fuel pump.
Canada Only
Be sure the posted octane is at least 87. If the octane is
less than 87, you may get a heavy knocking noise when
you drive. If it's bad enough, it can damage your engine.
If you're using fuel rated at 87 octane or higher and
you hear heavy knocking, your engine needs service.
But don't worry if you hear a little pinging noise when
you're accelerating or driving up a hill. That's normal,
and you don't have to buy a higher octane fuel to get
rid of pinging. It's the heavy, constant knock that means
you have a problem.If your vehicle is certified to meet California Emission
Standards (indicated on the underhood emission control
label), it is designed to operate on fuels that meet
California specifications. If such fuels are not available
in states adopting California emissions standards,
your vehicle will operate satisfactorily on fuels meeting
federal specifications, but emission control system
performance may be affected. The malfunction indicator
lamp on your instrument panel may turn on and/or your
vehicle may fail a smog
-check test. See ªMalfunction
Indicator Lampº in the Index. If this occurs, return to
your authorized GM dealer for diagnosis to determine
the cause of failure. In the event it is determined that the
cause of the condition is the type of fuels used, repairs
may not be covered by your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane
-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask your service station operator whether or
not the fuel contains MMT. General Motors does not
recommend the use of such gasolines. If fuels containing
MMT are used, spark plug life may be reduced and your
emission control system performance may be affected.
The malfunction indicator lamp on your instrument
panel may turn on. If this occurs, return to your
authorized GM dealer for service.

6-14
Engine Oil
If the CHECK ENG OIL
LEVEL light appears on the
instrument panel, it means
you need to check your
engine oil level right away.
For more information, see CHECK ENG OIL LEVEL in
the Index.
You should check your engine oil level regularly; this is
an added reminder.
Checking Engine Oil
It's a good idea to check your engine oil every time you
get fuel. In order to get an accurate reading, the oil must
be warm and the vehicle must be on level ground.
All Other Engines 8100 V8 Engine
The engine oil dipstick has a yellow ring handle and
is located on the passenger's side of the engine.
See ªEngine Compartment Overviewº in the Index
for more information.
Turn off the engine and give the oil several minutes to
drain back into the oil pan. If you don't, the oil dipstick
might not show the actual level.
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.

6-20
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.
Passenger Compartment Air Filter
(If Equipped)
Your vehicle may be equipped with a passenger
compartment air filter. The filter is located under the
instrument panel, below the glove compartment.
Your vehicle may or may not be equipped with an
access panel.
To replace the passenger compartment air filter,
do the following:
1. If your vehicle has an access panel, remove the bolts
on it and set the panel aside. If your vehicle does not
have the access panel, skip this step.
2. Next, pull downward
on the filter
retaining bracket.