light GMC JIMMY 1999 Manual Online

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4-47
Tow/Haul Mode (V6 Engine, Automatic
Transmission Equipped Models) (If Equipped)
The Tow/Haul Mode is a feature that assists when
pulling a heavy trailer. The purpose of the Tow/Haul
Mode is:

Reduce the frequency of shifts when pulling a
heavy trailer.

Provide the same shift feel when pulling a heavy
trailer as when the vehicle is unloaded.

Reduce the need to change throttle position when
pulling a heavy trailer.
This feature is turned on or off by pressing a button on
the floor console. When the feature is on, a light on the
instrument panel will illuminate to indicate that the
Tow/Haul Mode has been selected. See ªTow/Haul
Mode Lightº in the Index. The Tow/Haul Mode is
automatically turned off each time the vehicle is started.
The Tow/Haul Mode is most effective when the vehicle
and trailer combined weight is at least 75% of the Gross
Vehicle Weight Rating (GVWR) and the maximum
trailer weight rating for the vehicle. See ªGross Vehicle
Weight Ratingº and ªTrailer Weightº in the Index.The Tow/Haul Mode for hauling a heavy trailer is most
useful under the following conditions

When driving through hilly terrain at speeds below
55 mph (88 km/h).

When driving in low speed or stop and go traffic
below 55 mph (88 km/h).

When driving in parking lots.
Use the Tow/Haul Mode instead of the previous
recommendation to shift to THIRD (3) gear to improve
fuel economy at highway speeds and shift performance
at lower speeds. Operating in the Tow/Haul Mode when
not pulling a heavy trailer will not cause damage to the
vehicle, but you may experience reduced fuel economy
and undesirable performance from the engine and
transmission. The Tow/Haul Mode should be used only
when pulling a heavy trailer.

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4-56 Trailer Wiring Harness
The light-duty trailer wiring is a six-wire harness
assembly. The optional heavy
-duty trailer wiring is an
eight
-wire harness assembly. The harnesses are stored
under the vehicle, along the passenger
-side frame
crossmember on two
-door vehicles or on the driver's
side corner frame rear crossmember on four
-door
vehicles. The heavy
-duty trailer wiring has a 30-amp
feed wire with an inline fuse located by the junction
block. See ªFuses and Circuit Breakersº in the Index.
Both harnesses have no connector 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.

Dark Blue: Use for electric trailer brakes or
auxiliary wiring.

Red: Use for battery charging; it connects to the
starter solenoid (eight
-wire harness only).
Light Green: Back
-up lamps
(eight
-wire harness only).

Brown: Taillamps and parking lamps.

Yellow: Left stoplamp and turn signal.

Dark Green: Right stoplamp and turn signal.

White (Heavy Gauge): Ground wire.

White (Light Gauge): Auxiliary stoplamp.
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.

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5-3
Jump Starting
If your battery has run down, you may want to use
another vehicle and some jumper cables to start your
vehicle. But please use the following steps to do
it safely.
CAUTION:
Batteries can hurt you. They can be
dangerous because:

They contain acid that can burn you.

They contain gas that can explode or ignite.

They contain enough electricity to
burn you.
If you don't follow these steps exactly, some or all
of these things can hurt you.
NOTICE:
Ignoring these steps could result in costly
damage to your vehicle that wouldn't be covered
by your warranty.
The ACDelco Freedom battery in your vehicle
has a built
-in hydrometer. Do not charge, test or
jump start the battery if the hydrometer looks
clear or light yellow. Replace the battery when
there is a clear or light yellow hydrometer and a
cranking complaint.
Trying to start your vehicle by pushing or pulling
it won't work, and it could damage your vehicle.
1. Check the other vehicle. It must have a 12-volt
battery with a negative ground system.
NOTICE:
If the other system isn't a 12-volt system with a
negative ground, both vehicles can be damaged.

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5-4
2. Get the vehicles close enough so the jumper cables can
reach, but be sure the vehicles aren't touching each
other. If they are, it could cause a ground connection
you don't want. You wouldn't be able to start your
vehicle, and the bad grounding could damage the
electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on each vehicle. Put an
automatic transmission vehicle in PARK (P) or a
manual transmission vehicle in NEUTRAL (N). If
you have a four
-wheel-drive vehicle with the
Automatic Transfer Case, be sure the transfer case is
not in the NEUTRAL position.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter, or accessory power outlets, if you have this
option. Turn off all lamps that aren't needed as well
as radios. This will avoid sparks and help save both
batteries. In addition, it could save your radio!
NOTICE:
If you leave your radio on, it could be badly damaged.
The repair wouldn't be covered by your warranty.
4. Open both hoods and locate the batteries. Find the
positive (+) and negative (
-) terminals on each battery.
CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing this,
and some have been blinded. Use a flashlight if
you need more light.
Be sure the battery has enough water. You don't
need to add water to the ACDelco Freedom

battery installed in every new GM vehicle. But if
a battery has filler caps, be sure the right amount
of fluid is there. If it is low, add water to take care
of that first. If you don't, explosive gas could
be present.
Battery fluid contains acid that can burn you.
Don't get it on you. If you accidentally get it in
your eyes or on your skin, flush the place with
water and get medical help immediately.

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5-33 Rocking Your Vehicle To Get It Out
First, turn your steering wheel left and right. That will clear
the area around your front wheels. If you have a four
-wheel
drive vehicle, shift into 4HI. Then shift back and forth
between REVERSE (R) and a forward gear (or with a
manual transmission, between FIRST (1) or SECOND (2)
and REVERSE (R)), spinning the wheels as little as possible.
Release the accelerator pedal while you shift, and press
lightly on the accelerator pedal when the transmission is in
gear. By slowly spinning your wheels in the forward and
reverse directions, you will cause a rocking motion that may
free your vehicle. If that doesn't get you out after a few tries,
you may need to be towed out. Or, you can use your recovery
hooks if your vehicle has them. If you do need to be towed
out, see ªTowing Your Vehicleº in the Index.
Using the Recovery Hooks
Your vehicle may be equipped with recovery hooks.
The recovery hooks are provided at the front of your
vehicle. You may need to use them if you're stuck
off
-road and need to be pulled to some place where you
can continue driving.

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6-7
When you put the cap back on, turn it to the right
(clockwise) until you hear a clicking sound. Make
sure you fully install the cap. The diagnostic system
can determine if the fuel cap has been left off or
improperly installed. This would allow fuel to evaporate
into the atmosphere. See ªMalfunction Indicator Lampº
in the Index.
NOTICE:
If you need a new cap, be sure to get the right
type. Your dealer can get one for you. If you get
the wrong type, it may not fit properly. This may
cause your malfunction indicator lamp to light
and your fuel tank and emissions system may be
damaged. See ªMalfunction Indicator Lampº in
the Index.
Filling a Portable Fuel Container
CAUTION:
Never fill a portable fuel container while it is in
your vehicle. Static electricity discharge from the
container can ignite the gasoline vapor. You can
be badly burned and your vehicle damaged if this
occurs. To help avoid injury to you and others:

Dispense gasoline only into
approved containers.

Do not fill a container while it is inside a
vehicle, in a vehicle's trunk, pickup bed or
on any surface other than the ground.

Bring the fill nozzle in contact with the
inside of the fill opening before operating
the nozzle. Contact should be maintained
until the filling is complete.

Don't smoke while pumping gasoline.

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6-20 How to Add Fluid
Here's how to add fluid. Refer to the Maintenance
Schedule to determine what kind of fluid to use. See
ªRecommended Fluids and Lubricantsº in the Index.
1. Remove the filler plug.
2. Add fluid at the filler plug hole. Add only enough
fluid to bring the fluid level up to the bottom of the
filler plug hole.
3. Install the filler plug. Be sure the plug is fully seated.
Hydraulic Clutch
The hydraulic clutch system in your vehicle is
self
-adjusting. A slight amount of play (1/4 inch to
1/2 inch or 6 mm to 12 mm) in the pedal is normal.
It isn't a good idea to ªtop offº your clutch fluid.
Adding fluid won't correct a leak. A fluid loss in this
system could indicate a problem. Have the system
inspected and repaired.
When to Check and What to Use
Refer to the Maintenance Schedule, Owner Checks and
Services, to determine how often you should check the
fluid level in your clutch master cylinder reservoir and
for the proper fluid. See ªOwner Checks and Servicesº
and ªRecommended Fluids and Lubricantsº in
the Index.

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6-24
Radiator Pressure Cap
NOTICE:
Your radiator cap is a 15 psi (105 kPa)
pressure
-type cap and must be tightly installed to
prevent coolant loss and possible engine damage
from overheating. Be sure the arrows on the cap
line up with the overflow tube on the radiator
filler neck.
Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant system. The thermostat stops the
flow of coolant through the radiator until the coolant
reaches a preset temperature.
Engine Coolant
The cooling system in your vehicle is filled with
DEX
-COOL engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX
-COOL extended life coolant.
The following explains your cooling system and how
to add coolant when it is low. If you have a problem
with engine overheating, see ªEngine Overheatingº in
the Index.
A 50/50 mixture of clean, drinkable water and
DEX
-COOL coolant will:

Give freezing protection down to
-34F (-37C).

Give boiling protection up to 265F (129C).

Protect against rust and corrosion.

Help keep the proper engine temperature.

Let the warning lights and gages work as they should.

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6-32 Brake Wear
Your vehicle has four-wheel disc brakes.
Disc brake pads have built
-in wear indicators that
make a high
-pitched warning sound when the brake
pads are worn and new pads are needed. The sound may
come and go or be heard all the time your vehicle is
moving (except when you are pushing on the brake
pedal firmly).
CAUTION:
The brake wear warning sound means that soon
your brakes won't work well. That could lead to
an accident. When you hear the brake wear
warning sound, have your vehicle serviced.
NOTICE:
Continuing to drive with worn-out brake pads
could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly torque wheel nuts in the
proper sequence to GM specifications.
Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7 of this
manual under Part C ªPeriodic Maintenance
Inspections.º
Brake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in pedal
travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you make a brake stop, your disc brakes
adjust for wear.

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6-46 Uniform Tire Quality Grading
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance. (This
applies only to vehicles sold in the United States.) The
grades are molded on the sidewalls of most passenger
car tires. The Uniform Tire Quality Grading system does
not apply to deep tread, winter
-type snow tires,
space
-saver or temporary use spare tires, tires with
nominal rim diameters of 10 to 12 inches (25 to 30 cm),
or to some limited
-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to Federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specified government test course. For
example, a tire graded 150 would wear one and a half
(1 1/2) times as well on the government course as a tire
graded 100. The relative performance of tires depends
upon the actual conditions of their use, however, and
may depart significantly from the norm due to variations
in driving habits, service practices and differences in
road characteristics and climate.
Traction -- AA, A, B, C
The traction grades, from highest to lowest, are AA, A,
B, and C. Those grades represent the tire's ability to stop
on wet pavement as measured under controlled
conditions on specified government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight
-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.