1999 GMC C-SERIES lock

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NOTICE:
Don't put papers and other things that burn into
your ashtray. If you do, cigarettes or other
smoking materials could set them on fire,
causing damage.
Sun Visors
To block out glare, you can move the sun visors. You
can also swing them from side to side.
Auxiliary Power Jacks (If Equipped)
If your vehicle has these
power jacks, you'll find
them in the ashtray.These jacks provide 12
-volt power so you can operate
things such as a citizen's band (CB) radio or a cellular
phone. You'll see positive (red) and negative (black)
outlets. They have a 20
-amp fuse that is common with
the cigarette lighter. Don't use the cigarette lighter when
you're using a power jack because it may overload the
circuit and blow the fuse.
NOTICE:
Whether or not your vehicle has the power
outlets, don't plug in FM communications gear at
the ashtray area. FM equipment creates high
heat, and over time the area could get so hot that
wires could be damaged or a fire could even
break out.
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2-49
Trailer Connections (If Equipped)
These connections are located at the rear of the
cab. There is an air connection and a trailer
electrical connection.
Be sure that the couplings to the trailer are
made correctly.
Air Connections
The red line is the supply
line. It provides emergency
or constant air pressure. The
blue line is the control line,
providing service air.
Electrical Connections (If Equipped)
If your vehicle has this system, it has a seven-wire cable
that will go to the trailer to supply electrical power to
the trailer's lighting system. When not in use, it is stored
in the trailer air
-hose storage bracket.
NOTICE:
Starting in 1998, the center pin (also known as
the auxiliary circuit) of the 7
-pin trailer electrical
connector will be wired to provide continuous
power for the trailer anti
-lock brake systems
when the ignition key is in ON or RUN. Care
should be taken to insure that continuous power
on this circuit will not cause damage to the trailer
electrical system.
Consult with the trailer manufacturer for the
proper operation and checking procedures for
the trailer anti
-lock brake systems.
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2-61 Anti-Lock Brake System Warning Light
(Option)
With the anti-lock brake
system, this light will come
on when you start your
engine and it may stay on
for several seconds.
That's normal.
If the light stays on, or comes on when you're driving,
your vehicle needs service. If the PRIMARY BRAKE or
LOW AIR warning light isn't on, you still have brakes,
but you don't have the anti
-lock brake feature. If the
PRIMARY BRAKE and/or LOW AIR warning light is
on, you don't have anti
-lock brakes and there's a
problem with your regular brakes. See ªBrake System
Warning Lightº earlier in this section.
The anti
-lock brake system warning light should come
on briefly when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.
Engine Coolant Temperature Gage
Gasoline Engine Diesel Engine
This gage shows the engine coolant temperature. If
the gage pointer moves into the red area, your engine
coolant might have overheated and your engine may be
too hot. You should pull off the road, stop your vehicle
and turn off the engine as soon as possible.
See ªEngine Overheatingº in the Index. If you have a
Caterpillar

diesel engine, also see your Caterpillar

Operation & Maintenance Manual.
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2-63 Intake Heater Indicator Light
(Diesel Engines)
This light on the instrument
panel will come on when
the intake heater is on and
the ignition key is in ON.
Since the light is illuminated whenever the intake heater
is activated, it is normal for the light to cycle on and off
as the heater cycles during engine warm
-up. See
ªEngine Startingº in your Caterpillar
Operation &
Maintenance Manual for more information.
Diff Lock Indicator Light (If Equipped)
This light on the instrument
panel is on when the
inter
-axle differential lock
system is in use.
The light will come on momentarily during starting.
If the light fails to come on, have it repaired as soon as
possible so you will be aware when the lock system is
in use.
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2-70 Filterminder Gage (Diesel Engine)
This optional gage is in the
lower center of the
instrument panel. It
monitors the engine
air filter.
As the filter gets dirty, the yellow indicator will begin to
rise. When it reaches 25 inches of vacuum on the scale,
the filter should be replaced.
After replacing the filter, reset the gage by pressing in
the yellow reset pin at the bottom of the gage.
If you have a diesel engine, also see your Caterpillar


Operation & Maintenance Manual.
Hourmeter Gage (If Equipped)
If your vehicle has this
gage, it will be to the lower
left of the steering column,
mounted on a bracket either
above or below the fuse
block. It shows the total
engine operating time.
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3-
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3-1
Section 3 Comfort Controls and Audio Systems
In this section, you'll find out how to operate the comfort control and audio systems offered with your vehicle.
Be sure to read about the particular systems supplied with your vehicle.
3
-2 Comfort Controls
3
-5 Air Conditioning
3
-5 Heating
3
-6 Defogging
3
-6 Ventilation System
3
-7 Audio Systems
3
-7 Setting the Clock3
-8 AM/FM Stereo
3
-10 Remote Cassette Tape Player (If Equipped)
3
-10 Understanding Radio Reception
3
-11 Tips About Your Audio System
3
-12 Care of Your Cassette Tape Player
3
-12 Fixed Mast Antenna
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3-7
Ventilation Tips

Keep the hood and front air inlet free of ice, snow or
any other obstruction (such as leaves). The heater
and defogger will work far better, reducing the
chance of fogging the inside of your windows.

When you enter a vehicle in cold weather, turn the
blower fan to high for a few moments before driving
off. This helps clear the intake ducts of snow and
moisture and reduces the chance of fogging the
inside of your windows.

Keep the air path under the seats clear of objects.
This helps air to circulate throughout your vehicle.
The air vents are located in the center and on the sides of
your instrument panel. You can move the vents to direct
the flow of air or close the vents altogether. When you
close a vent, it will increase the flow of air coming out
of any vents that are open.
If your vehicle does not have air conditioning, there are
air vent controls located below the instrument panel.Audio Systems
Your Delco Electronics audio system has been designed
to operate easily and give years of listening pleasure.
You will get the most enjoyment out of it if you acquaint
yourself with it first. Find out what your Delco
Electronics system can do and how to operate all its
controls, to be sure you're getting the most out of the
advanced engineering that went into it.
Setting the Clock
While pressing the SET button, press the UP button
until the correct hour appears on the display and the
DOWN button until the correct minute appears on the
display. If you press and hold the UP/DOWN button,
hours or minutes will advance rapidly.
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3-8 AM-FM Stereo
Playing the Radio
ON
-OFF: Press the round button to turn the radio on.
Press it again to turn the radio off.
VOLUME: Slide the VOLUME lever to the right to
increase volume or to the left to decrease volume.
CALL: Press this button to display the clock for
a few seconds when the radio is on. To change what is
normally shown on the display (station or time), press
this button and the SET button.Finding a Station
AM/FM: Press this button to switch between AM and
FM. The display shows your selection.
TUNE: Press UP to increase the frequency of a radio
station and DOWN to decrease the frequency of a radio
station. If you press and hold the UP or DOWN button
for more than half a second, the radio will tune rapidly
in that direction.
SEEK: Press SEEK to tune the radio to the next higher
station and stay there.
SCAN: Press SCAN to listen to the next higher
radio station for a few seconds. Press SCAN again
to stop scanning.
PUSHBUTTONS: The six numbered pushbuttons
let you return to your favorite stations. You can set up to
12 stations (six AM and six FM). Just:
1. Turn the radio on.
2. Press AM/FM to select a band.
3. Tune in the desired station.
4. Press SET. (SET will appear on the display and will
blink for about eight seconds.)
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