brake GMC C-SERIES 1999 Owner's Manual

yellowblue
2-30
Running Your Engine While You're
Parked (Automatic Transmission)
It's better not to park with the engine running. But if
ever you have to, here are some things to know.
CAUTION:
Idling the engine with the climate control system
off could allow dangerous exhaust into
your vehicle (see the earlier Caution under
ªEngine Exhaustº).
Also, idling in a closed-in place can let deadly
carbon monoxide (CO) into your vehicle even if
the fan switch is at the highest setting. One place
this can happen is a garage. Exhaust
-- with
CO
-- can come in easily. NEVER park in a
garage with the engine running.
Another closed-in place can be a blizzard.
(See ªBlizzardº in the Index.)
CAUTION:
It can be dangerous to get out of your vehicle
without the parking brake firmly set. Your
vehicle can roll. If you've left the engine running,
the vehicle can move suddenly. You or others
could be injured. To be sure your vehicle won't
move, even when you're on fairly level ground,
always set your parking brake.
Follow the proper steps to be sure your vehicle
won't move.
Windows
Manual Windows
Turn the hand crank on each door to raise or lower
the window.
ProCarManuals.com

yellowblue
2-36 Cruise Control (If Equipped)
With cruise control, you can
maintain a speed of about
30 mph (48 km/h) or more
without keeping your foot
on the accelerator. Cruise
control does not work at
speeds below about 30 mph
(48 km/h).
If you have an automatic transmission and you apply
your brakes, the cruise control will shut off.
If you have a manual transmission and you apply your
brakes or push the clutch pedal, the cruise control will
shut off.CAUTION:

Cruise control can be dangerous where you
can't drive safely at a steady speed. So,
don't use your cruise control on winding
roads or in heavy traffic.

Cruise control can be dangerous on
slippery roads. On such roads, fast changes
in tire traction can cause needless wheel
spinning, and you could lose control. Don't
use cruise control on slippery roads.
ProCarManuals.com

yellowblue
2-37
Setting Cruise Control
CAUTION:
If you leave your cruise control switch on when
you're not using cruise, you might hit a button
and go into cruise when you don't want to. You
could be startled and even lose control. Keep the
cruise control switch off until you want to use it.
1. Move the cruise control switch to ON.
2. Get up to the speed you want.
3. Press in the SET button at the end of the lever and
release it.
4. Take your foot off the accelerator pedal.Resuming a Set Speed
Once you're going about 30 mph (48 km/h) or more,
you can move the cruise control switch from ON to
R/A (Resume/Accelerate) for about half a second.
The vehicle will return to your chosen speed and
stay there.
If you hold the switch at R/A longer than half a second,
the vehicle will keep going faster until you release the
switch or apply the brake, so unless you want to go
faster, don't hold the switch at R/A.
If the switch is held at R/A for longer than 200 seconds,
the cruise control will automatically turn off. The cruise
control function will be made available again the next
time the engine is restarted.
ProCarManuals.com

yellowblue
2-39
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.
ProCarManuals.com

yellowblue
2-40
CAUTION:
Using the trailer brake hand control for parking
or for holding the vehicle on a hill may not keep
the vehicle from rolling. This can happen if
someone hits the valve by accident, or if air
pressure bleeds from the system. If the vehicle
rolls, you or others could be injured. To park the
vehicle or hold it on a hill, use the parking
brake properly.
Inter-Axle Differential Lock Control
(If Equipped)
If your vehicle has this
feature, the control is
located at the lower
right corner of the
instrument panel.
If you're approaching a slippery surface where it looks
like one or even all of the wheels may start to slip, you
can use this control. It locks your rear differentials so
that power is transmitted equally to both rear axles.
ProCarManuals.com

yellowblue
2-44
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.
ProCarManuals.com

yellowblue
2-45
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.
ProCarManuals.com

yellowblue
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.
ProCarManuals.com

yellowblue
2-51
A. Left Side Window Defogger
B. Main Lamps Switch
C. Vent
D. Instrument Cluster
E. Warning Lights
F. Heated Mirror Switch (Option)
G. Exhaust Brake Switch (Option)
H. Marker/Clearance Lamps Switch (Option)
I. Audio System or Storage Area
J. VentsK. Glove Box
L. Right Side Window Defogger
M. Storage Tray/Cassette Player
N. Comfort Controls
O. Air Brake Controls (If Equipped)
P. Ashtray
Q. Air Vent Controls
R. Convenience Center Fuse Panel
S. Hourmeter (Option)
ProCarManuals.com

yellowblue
2-56 Charging System Indicator Light
CAUTION:
If your vehicle has an electric/hydraulic parking
brake, do not drive if the charging system light is
on. If the battery drains too much, the parking
brake can suddenly come on and stop the vehicle.
This can cause severe injury to you and others.
The charging system light is
located in the center of the
instrument cluster just
above the odometer.
It should come on briefly when you turn on the ignition,
before the engine is running, as a check to show that it
is working.If it stays on, or comes on while you are driving, have it
checked right away. You could have a loose generator
drive belt or some other problem.
Driving while this light is on could drain your battery. If
you must drive a short distance with the light on, turn
off your radio and other accessories.
Sustained driving with a generator failure could result in
a lack of back
-up braking if the engine quits or the
power steering pump should fail.
Voltmeter
When your engine is
running, the voltmeter gage,
at the lower left of the
instrument cluster, shows
the charging system voltage.
Readings in either warning zone indicate a possible
problem in the electrical system.
ProCarManuals.com