1999 GMC C-SERIES light

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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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Low Speed Delay Wipers (If Equipped)
You can set the wiper speed
for a long or short delay
between wipes. This can be
very useful in light rain or
snow. Turn the band to
choose the delay time.
The closer to LO, the
shorter the delay.
Heavy snow or ice can overload your wipers. Clear
away snow or ice to prevent bending or breaking the
wiper linkage.
Windshield Washer
At the top of the multifunction lever, there's a paddle
with the word PUSH on it. To spray washer fluid on the
windshield, push the paddle.
CAUTION:
In freezing weather, don't use your washer until
the windshield is warmed. Otherwise the washer
fluid can form ice on the windshield, blocking
your vision.
If you have the standard wipers, the wipers will keep
going in LO until you turn the wiper control to the
off symbol.
If you have the low
-speed delay option, the wipers will
clear the window and then either stop or return to your
preset speed.
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Using Cruise Control on Hills
How well your cruise control will work on hills depends
upon your speed, load and the steepness of the hills.
When going up steep hills, you may want to step on the
accelerator pedal to maintain your speed. When going
downhill, you may have to brake or shift to a lower gear
to keep your speed down. Of course, applying the brake
or clutch takes you out of cruise control. Many drivers
find this to be too much trouble and don't use cruise
control on steep hills.
Ending Cruise Control
There are different ways to turn off the cruise control:

Step lightly on the brake pedal.

Push the clutch pedal, if you have a
manual transmission.

Move the cruise switch to OFF.
Erasing Speed Memory
When you turn off the ignition, your cruise control set
speed memory is erased.Trailer Brake Hand Control Valve
(Option)
If your vehicle has this feature, it is mounted on the
steering column.
This control lets you apply the trailer brakes without
applying the tractor brakes. You can apply the trailer
brakes a little or apply them all the way if you have to.
Use this control only when you're driving. Don't use it
for parking or to hold the rig on a hill.
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Let up on the accelerator before you turn on your
inter
-axle differential lock. When you turn on this
control, the DIFF LOCK indicator on the instrument
panel will light.
NOTICE:
Activating the inter-axle differential lock when
the rear wheels are actually spinning freely, as
they might on ice or snow, can cause you to lose
control of the vehicle. It can also damage the
axles. Turn on this control only when the wheels
are not spinning freely.
Rear Axle Differential Lock Control
(If Equipped)
If your vehicle has a
Controlled Traction or
Locking Differential axle,
the control is located at the
lower right corner of the
instrument panel. You'll see
this control on single rear
axle vehicles.
If you're approaching a slippery surface where it looks
like one or even both wheels may start to slip, you can
use this control. It locks your rear differential so that
power is transmitted equally to both rear wheels.
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Let up on the accelerator before you turn on your rear
axle differential lock.
NOTICE:
Activating the rear-axle differential lock when
the rear wheels are actually spinning freely, as
they might on ice or snow, can cause you to lose
control of the vehicle. It can also damage the axle.
Turn on this control only when the wheels are not
spinning freely.
Engine Air Control (If Equipped)
If your vehicle has this control, the handle is located on
the instrument panel just to the right of the steering
wheel. The control is activated by pulling the handle out
and turning slightly in either direction to lock it.
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Press the top left switch to turn on your:

Parking Lamps

Marker Lamps (unless your vehicle has the optional
marker and clearance lamps switch)

Taillamps

Instrument Panel Lights

License Plate Lamps
Push the bottom left switch to turn on the headlamps, as
well as all of the lamps just listed. Push the switch
marked with the ªOº symbol to turn off your lamps.
Move the thumbwheel to the right of the off switch
down to dim your instrument panel lights. Moving this
wheel up makes these lights brighter. Moving it all the
way up will make the interior lamp come on.
A circuit breaker protects your headlamps. If you have
an electrical overload, your headlamps will flicker on
and off. Have your headlamp wiring checked right away
if this ever happens.Headlamps On Reminder (If Equipped)
If you have this system, a tone alarm will sound when
your headlamps and/or parking lamps are turned on and
your ignition is in OFF, LOCK or ACCESSORY.
Daytime Running Lamps (If Equipped)
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the day.
DRL can be helpful in many different driving
conditions, but they can be especially helpful in the
short periods after dawn and before sunset.
The high and low
-beam headlamps will come on at
reduced brightness in daylight when:

The ignition is on,

The headlamp switch is off and

The parking brake is released.
When the DRL are on, only your low
-beam headlamps
will be on. The exterior lamps won't be on. Your
instrument panel won't be lit up either.
When it begins to get dark, your DRL indicator light is a
reminder to turn your headlamp switch on. The other
lamps that come on with your headlamps will also
come on.
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When you turn the headlamp switch off, the regular
lamps will go off, and your low
-beam headlamps will
change to the reduced brightness of DRL.
To idle your vehicle with the DRL off, set the parking
brake. The DRL will stay off until you release the
parking brake.
As with any vehicle, you should turn on the regular
headlamp system when you need it.
Marker and Clearance Lamps Switch
(If Equipped)
Your vehicle will have this
switch only if it is designed
to pull a trailer. If it has this
switch, you'll find it on the
upper right side of your
instrument panel, just above
the radio.If your vehicle has no radio, the switch is just above the
storage area. Use the switch to operate your clearance
and marker lamps. The marker lamps are illuminated
when the indicator light is on.
Your headlamps switch will not operate these lamps.
You can use the switch to manually blink the marker and
clearance lamps by simply turning it on and off.
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