1999 GMC C-SERIES tow

yellowblue
1-2
Seats and Seat Controls
This section tells you about the seats in your vehicle and
how to adjust them.
CAUTION:
You can lose control of the vehicle if you try to
adjust the seat while the vehicle is moving. The
sudden movement could startle and confuse you,
or make you push a pedal when you don't want
to. Adjust the driver's seat only when the vehicle
is not moving.
Bucket and Bench Seats
If your vehicle has a bucket or bench seat, you can
adjust it with this lever at the front of the seat.
Slide the lever toward the outer seat support to unlock it.
Slide the seat to where you want it. Then, release the
lever and try to move the seat with your body to make
sure the seat is locked into place.
ProCarManuals.com

yellowblue
1-3 Head Restraints
Some seats have adjustable head restraints. Slide an
adjustable head restraint up or down so that the top of
the restraint is closest to the top of your ears. This
position reduces the chance of a neck injury in a crash.
Seatback Latches
The front of the full-width bench seat seatback folds
forward to let you reach the rear of the cab. Bucket seats
have outboard
-mounted levers to tilt the seatbacks
forward or rearward.
Your seatback will move back and forth freely unless
you come to a sudden stop
-- then it will lock into place.
If your vehicle is parked going down a fairly steep hill,
the seatback may not fold without some help from you.
To fold the seatback
forward, push the seatback
toward the rear of the
vehicle as you lift this latch.
The latch must be down for
the seat to work properly.
Bench Seat Shown
CAUTION:
If the seatback isn't locked, it could move
forward in a sudden stop or crash. That could
cause injury to the person sitting there. Always
press rearward on the seatback to be sure it
is locked.
ProCarManuals.com

yellowblue
1-5
To adjust the height of the
cushion, lift the cushion
height adjustment handle up
and forward. You can
choose between two
settings. The handle is
located underneath the seat,
in the front.
Lumbar Adjustments
To get more support in the
lumbar area of your back,
turn the lumbar adjustment
knob. The knob is located
on the upper cushion, on the
inboard side of the driver's
seat and the outboard side
of the passenger's seat.Seatback Adjustment
To tilt the seatback, turn the
backrest tilt knob. The knob
is located on the lower
cushion, on the outboard
side of the driver's seat and
the inboard side of the
passenger's seat.
Fore
-and-Aft Adjustment
To slide the seat forward or
backward, move the lever
toward the passenger's side.
The seat will lock in at
1/2 inch (1.5 cm)
increments. The lever is
located underneath the seat,
in the front.
ProCarManuals.com

yellowblue
1-26
Child Restraints
Every time infants and young children ride in vehicles,
they should have protection provided by
appropriate restraints.
Q:What are the different types of add-on
child restraints?
A:Add-on child restraints are available in four basic
types. When selecting a child restraint, take into
consideration not only the child's weight and size,
but also whether or not the restraint will be
compatible with the motor vehicle in which it will
be used.
An infant car bed (A) is a special bed made for use
in a motor vehicle. It's an infant restraint system
designed to restrain or position a child on a
continuous flat surface. With an infant car bed,
make sure that the infant's head rests toward the
center of the vehicle.
ProCarManuals.com

yellowblue
1-34
CAUTION:
Never do this.
Here two children are wearing the same belt. The
belt can't properly spread the impact forces. In a
crash, the two children can be crushed together
and seriously injured. A belt must be used by
only one person at a time.
Q:What if a child is wearing a lap-shoulder belt,
but the child is so small that the shoulder belt is
very close to the child's face or neck?
A:Move the child toward the center of the vehicle, but
be sure that the shoulder belt still is on the child's
shoulder, so that in a crash the child's upper body
would have the restraint that belts provide. If the
child is so small that the shoulder belt is still very
close to the child's face or neck, you might want to
place the child in a seat that has a lap belt, if your
vehicle has one.
ProCarManuals.com

yellowblue
2-7
ACCESSORY (A): This position lets you use
accessories when the engine is off. To use
ACCESSORY, push in the key and turn it toward you.
LOCK (B): This position locks your ignition. You will
be able to remove your key only when the switch is in
this position.
OFF (C): This position lets you turn off the engine, but
the key can't be removed.
RUN (D): This is the position for driving and activating
the CAT diesel air inlet heater (if equipped).
START (E): This position starts your engine.
Engine Starter Over-Crank Protection
(If Equipped)
Some vehicles have an engine starter over-crank
protection system. This system includes a built
-in
temperature limiting switch to prevent internal damage
to the starter. If the starter motor overheats and shuts
off due to over
-cranking, the motor must cool down
before the switch will reset and allow you to operate the
starter. It can take up to six minutes before the starter
will work again.
Starting Your Gasoline Engine
Engines start differently. The 8th digit of your Vehicle
Identification Number (VIN) shows the code letter for
your engine. (See ªVehicle Identification Numberº in
the Index.) Follow the proper steps to start the engine.
To start a diesel engine, see ªStarting Your Diesel
Engineº in the Index.
Automatic Transmission
Set the parking brake and move your shift lever to
NEUTRAL (N) or PARK (P) if so equipped. Your
engine won't start in any other position
-- that's a
safety feature.
ProCarManuals.com

yellowblue
2-9
NOTICE:
Your engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way
the engine operates. Before adding electrical
equipment, check with your dealer. If you don't,
your engine might not perform properly.
If you ever have to have your vehicle towed, see
the part of this manual that tells how to do it
without damaging your vehicle. See ªTowing
Your Vehicleº in the Index.
Gasoline Engine Warm-Up
When you've started your engine, let it run for 20 or
30 seconds to warm up before you put a load on
the engine.
Drive at moderate speeds for the first few miles,
especially in cold weather. Running a cold engine at
high speed can damage it.
Restarting the Gasoline Engine While
Moving (Automatic Transmission)
If you have to restart the engine while the vehicle is
moving, you'll first have to shift the automatic
transmission to NEUTRAL (N). This safety feature
prevents starting the engine when the transmission is in
a drive gear.
Stopping the Gasoline Engine
Let your engine idle for a few seconds before turning it
off after you have finished driving your vehicle.
If you shift to NEUTRAL (N), set the parking brake.
If you shift to PARK (P), the auto
-apply feature will set
the parking brake.
If your vehicle has a two
-speed axle, put the range
selector in LOW. To be sure the axle has shifted into
LOW, engage the clutch and transmission the vehicle
may move slightly when you do this.
While your engine is idling before you turn it off, you
can make a list of any operational or handling concerns
to give to responsible maintenance personnel so they can
handle them right away.
Moisture will condense in a fuel tank that is almost
empty if the vehicle is not run for a while, even just
overnight under some conditions. So, it's always best to
refuel your vehicle at the end of each run.
ProCarManuals.com

yellowblue
2-10
Starting Your Diesel Engine
If you have a Caterpillar diesel engine, also refer to
your Caterpillar
Operation & Maintenance Manual for
starting procedure.
To make starting easier in cold weather (below 32F or
0C), the proper viscosity engine oil should be used. It's
also best to heat the engine oil first. You can do this by
using an engine coolant heater. A GM Automatic Ether
Injection System aids cold weather starting.
NOTICE:
Your diesel engine has an electric air intake
heater system which reduces white smoke and
helps start the engine in cold weather. Do not
spray starting fluid into the air intake where it
can contact the heater elements.
If you don't have the GM Automatic Ether
Injection System, don't use starting fluid or
you could damage your engine. If you have the
GM system, use only GM approved starting fluid
that has been tested to establish compatibility
with the air inlet heater system.
NOTICE:
If you ever have to have your vehicle towed, see
the part of this manual that tells how to do it
without damaging your vehicle. See ªTowing
Your Vehicleº in the Index.
Restarting the Diesel Engine While Moving
(Automatic Transmission)
If you have to restart the engine while the vehicle is
moving, you'll first have to shift the automatic transmission
to NEUTRAL (N). This safety feature prevents starting
the engine when the transmission is in a drive gear.
Stopping the Diesel Engine
If you have a Caterpillar diesel engine, see your
Caterpillar
Operation & Maintenance Manual.
1. Set the parking brake and shift to NEUTRAL (N) or
PARK (P).
2. Turn the ignition switch key to OFF.
If your vehicle has a two
-speed axle, see ªRear Axle,
Tw o
-Speed Electric Shift Controlº or ªRear Axle,
Tw o
-Speed Airshift Controlº in the Index.
ProCarManuals.com