1999 GMC C-SERIES towing

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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.
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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.
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If your vehicle has this
system, you will have a
knob to the right of the
steering column.
To apply the parking brake, pull the knob toward you.
Then shift the transmission to NEUTRAL (N) or
PARK (P).
Push the knob in to release the parking brake. The
ignition must be in RUN and the shift lever out of
PARK (P) in order to release the parking brake.
The parking brake will automatically apply if the
ignition is turned off and in PARK (P) and will also
apply (will not release) if the vehicle's battery is dead
or disconnected.The PARK BRAKE light may flash while the parking
brake is being applied or released. This is normal for
this system.
If your vehicle needs towing or the parking brake will
not release, the towing operator will need to disconnect
the propshaft before towing your vehicle. See ªTowing
Your Vehicleº in the Index.
Air Brake (If Equipped)
CAUTION:
When the yellow SYSTEM PARK and the red
TRAILER AIR SUPPLY knobs are both pushed
in, your rig will be free to move. It could strike
someone or something. When both of these knobs
are pushed in, either hold the regular brake
pedal down or, if you have it, pull out the blue
TRACTOR PARKING knob, to keep your rig
from moving.
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If your vehicle has air
brakes, you will have this
control. Pulling it out
applies the parking brake.
The PARK BRAKE light
will come on when the air
parking brake is applied.
Vehicles built for use as tractors or towing vehicles have
one or two more air brake controls. They look like this:To charge a trailer's air brake system:
1. Move your tractor into the proper position. Apply the
parking brake by pulling the yellow SYSTEM PARK
knob out.
2. Hook up the trailer air system properly.
3. Get into the tractor. Push and hold down the regular
brake pedal.
4. Push in both the yellow SYSTEM PARK and the red
TRAILER AIR SUPPLY knobs. This will charge
your trailer's air system.
If you have the blue TRACTOR PARKING knob,
pull it out to set the tractor brakes while the air system
is charging.
After a few minutes, the trailer system should be fully
charged. When it is, the air pressure gage will show
about 125 to 135 psi (862 to 931 kPa) and you may hear
the ªpop offº valve operate.
For driving with a trailer, the yellow, red and blue
(if equipped) knobs all must be pushed in. It's the same
when you're not pulling a trailer except that the red
TRAILER AIR SUPPLY knob must be out.
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CAUTION:
If you apply any one of the air brake parking
controls while the vehicle is moving, your rig will
stop suddenly. If you are not ready for this, you
or others could be injured. Don't apply any one
of these controls while you're driving, unless you
have to make an emergency stop.
If the air pressure drops below 60 to 70 psi (413 to
482 kPa), the PRIMARY BRAKE light will come on. If
the air pressure drops to 40 to 45 psi (275 to 309 kPa), the
yellow knob will automatically pop out and apply the
spring brakes. If you ever have a complete loss of air so
that your air brakes automatically apply, there is a way that
the tow operator can release the parking brakes to tow the
vehicle. See ªTowing Your Vehicleº in the Index.
CAUTION:
If your vehicle is left in gear, the engine can
start if the vehicle starts to roll. This can easily
happen if you have the diesel engine. Shift the
transmission into NEUTRAL (N) before you
leave the vehicle.
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Hydraulic Brake System Warning Lights
Vehicles with hydraulic systems have two brake system
warning lights on the instrument panel.
If the PRIMARY BRAKE
warning light comes on, it
means that the fluid level in
the master cylinder
reservoir is low or there is
another problem with your
primary hydraulic brakes.
When it comes on, you will also hear a warning tone.
The PRIMARY BRAKE warning light may come on,
and the warning tone may sound, when you're turning
and braking at the same time. This is normal. See
ªHydraulic Brake Systemsº in the Index.
If the AUX BRAKE
warning light comes on, it
means that there is
something wrong in the
auxiliary brake system.
When this light comes on, you will also hear a warning tone.Both of these lights should come on briefly every time
you start the engine. If they don't come on then, have
them fixed so they will be ready to warn you if there's a
problem. If one or both of these warning lights stay on
after you start the engine, there could be a brake
problem. Have your brake system inspected right away.
If one or both of these lights come on and stay on while
you are driving, pull off the road and stop carefully. You
may notice that the pedal is harder to push. Or, the pedal
may go closer to the floor. It may take longer to stop.
If either light is still on, have the vehicle towed for
service. (See ªTowing Your Vehicleº in the Index.)
See ªHydraulic Brake Systemsº in the Index for
more information.
CAUTION:
Your brake system may not be working properly
if a brake system warning light is on. Driving
with either of the brake system warning lights on
can lead to an accident. If either light is still on
after you've pulled off the road and stopped
carefully, have the vehicle towed for service.
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5-
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Section 5 Problems on the Road
Here you'll find what to do about some problems that can occur on the road.
5
-2 Hazard Warning Flashers
5
-3 Other Warning Devices
5
-5 Jump Starting
5
-9 Towing Your Vehicle
5
-18 Engine Overheating
5
-20 Cooling System (Gasoline Engine)5
-27 Cooling System (Diesel Engine)
5
-33 Engine Fan Noise
5
-34 If a Tire Goes Flat
5
-34 Changing a Flat Tire
5
-37 If You're Stuck: In Sand, Mud, Ice or Snow
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A. Heavy Metal Engine Part
B. Good Battery
C. Dead Battery
Towing Your Vehicle
Try to have a GM dealer or a professional towing
service tow your vehicle. They can provide the right
equipment and know
-how to tow it without damage.
Before you do anything, turn on the hazard warning
flashers (if they have not been damaged).
When you call, tell the towing service:

The make, model and year of your vehicle.

Whether you can still move the shift lever.

If there was an accident, what was damaged.
When the towing service arrives, let the tow operator
know that this manual contains detailed towing
instructions. The operator may want to see them.
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