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The accelerator and clutch pedals must be released in
order for the exhaust brake to engage. Whenever the
exhaust brake is active, the light in the switch will be on.
Do not use the exhaust brake when running the engine at
idle during warm
-up or other extended periods.
Prolonged use of the exhaust brake during idling will
cause the engine to overheat.
CAUTION:
Be careful when using the exhaust brake or you
could lock the wheels and lose control of the
vehicle. Operators not familiar with an exhaust
brake should not use this brake on slippery
surfaces before learning to use it on dry surfaces.
If the vehicle's wheels begin to lock when using
the exhaust brake on slippery surfaces, switch the
exhaust brake off immediately. The exhaust
brake will turn off if the anti
-lock brake system
is activated.
Tw o-Speed Rear Axle Electric Shift
Control (If Equipped)
If your vehicle has this feature, you'll find a label (or
labels) on the ceiling above the windshield or in another
place near the driver that show how to use it. Be sure
to follow the directions carefully. Use the following
directions based on the type of shift control you have.
Automatic Transmission
The switch for the rear axle
shift control is on the shift
tower to the right of the
shift lever.
When the switch is up, the rear axle is in the high range.
Push it down to get the low range.
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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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An arrow on the instrument panel will flash in the
direction of the turn when the lever is in the up or
down position.
This system replaces the turn signal feature of the
multifunction lever only. All other features such as
headlamp high/low beam, windshield wipers and
washer, etc. remain part of the multifunction system.
If you have this system, see ªSignal
-Stat Turn Signal
and Hazard Warning Flasherº in the Index to find out
how the hazard warning flasher portion works.
Headlamp High/Low Beam Changer
To change the headlamps from low beam to high, push
the multifunction lever away from you. To switch back
to low beam, pull the lever toward you.
When the high beams are
on, a light on the instrument
cluster will also be on.
Windshield Wipers
The windshield wipers are controlled by turning the
band with the wiper symbol on it.
For a single wiping cycle, turn the band to MIST. Hold
it there until the wipers start, then let go. The wipers will
stop after one cycle. If you want more cycles, hold the
band on MIST longer.
For steady wiping at low speed, turn the band away
from you to the LO position. For fast wiping, turn the
band to HI. To stop the wipers, turn the band to the
off symbol.
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Interior Lamps
Dome Lamp
The dome lamps will come on when you open the
driver's door. You can also turn the dome lamps on by
turning the interior lamp dimmer dial all the way up
until it clicks.
Mirrors
Inside Rearview Mirror (If Equipped)
Press the tab under the mirror to reduce glare at night
from headlamps behind you.
Outside Mirrors
Adjust the outside mirror or
mirrors by hand so you can
just see the side of your
vehicle when you're sitting
in the driver's seat. These
mirrors can fold in toward
the vehicle for entering
narrow garages and for
clearance in an automatic
vehicle wash.
If your mirrors have the clearance lamps, they'll be on
when your parking lamps are on.
Convex Outside Mirrors (Option)
Your vehicle may have optional convex mirrors. A
convex mirror's surface is curved so you can see more
from the driver's seat.
CAUTION:
A convex mirror can make things (like other
vehicles) look farther away than they really are.
If you cut too sharply into the right or left lane,
you could hit a vehicle. Check your regular
outside mirrors (or your inside mirror, if you
have one) before changing lanes.
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Readings in the low warning zone may occur when a
large number of electrical accessories are operating
in the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system may not be able to provide full
power at engine idle. As engine speeds are increased,
this condition should correct itself because higher
engine speeds allow the charging system to create
maximum power.
You can only drive a short time on the battery. Be sure
to shut off the radio, the fan or any unnecessary
accessories and have the system serviced.
Do Not Shift Warning Light
If your vehicle has the
Allison MD automatic
transmission, certain
transmission malfunctions
will turn this light on.If this light comes on while you are driving, do not use
the transmission shift control. Using the transmission
shift control will result in the loss of forward gears. The
computer for the transmission senses a problem and
chooses a gear to stay in so that you can drive the
vehicle in that gear. You may not be able to drive as fast
or back up when this light is on.
NOTICE:
If the DO NOT SHIFT warning light comes on
while you are driving, it is a warning that making
a transmission ªrangeº change could leave you
stranded. The vehicle may not continue to move
if you change gears with the transmission shift
control. The transmission can't operate in all
gears because something is wrong. Leave the shift
control alone and drive directly to a GM dealer
for service. If you can't go in for service
immediately, have the vehicle towed.
Brake System Warning Light
Your vehicle has either hydraulic or air brakes. Each
system has different warning lights.
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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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