1999 GMC SAFARI sensor

1-33 Servicing Your Air Bag-Equipped Vehicle
Air bags affect how your vehicle should be serviced.
There are parts of the air bag system in several places
around your vehicle. You don't want the system to
inflate while someone is working on your vehicle.
Your dealer and the service manual have information
about servicing your vehicle and the air bag system.
To purchase a service manual, see ªService and Owner
Publicationsº in the Index.
CAUTION:
For up to 10 minutes after the ignition key is
turned off and the battery is disconnected, an air
bag can still inflate during improper service. You
can be injured if you are close to an air bag when
it inflates. Avoid wires wrapped with yellow tape
or yellow connectors. They are probably part of
the air bag system. Be sure to follow proper
service procedures, and make sure the person
performing work for you is qualified to do so.
The air bag system does not need regular maintenance.
Adding Equipment to Your Air
Bag-Equipped Vehicle
Q:If I add a push bumper or a bicycle rack to
the front of my vehicle, will it keep the air bags
from working properly?
A:As long as the push bumper or bicycle rack is
attached to your vehicle so that the vehicle's basic
structure isn't changed, it's not likely to keep the
air bags from working properly in a crash.
Q:Is there anything I might add to the front of
the vehicle that could keep the air bags from
working properly?
A:Yes. If you add things that change your vehicle's
frame, bumper system, front end sheet metal or
height, they may keep the air bag system from
working properly. Also, the air bag system may not
work properly if you relocate any of the air bag
sensors. If you have any questions about this, you
should contact Customer Assistance before you
modify your vehicle. (The phone numbers and
addresses for Customer Assistance are in Step Two of
the Customer Satisfaction Procedure in this manual.
See ªCustomer Satisfaction Procedureº in the Index.)

2-40
Turn the knob clockwise to the master lighting symbol
to turn on all the lamps listed as well as the headlamps.
Turn the knob all the way counterclockwise to turn off
your lamps and put the system in auto headlamp mode.
Automatic Headlamp System
When it is dark enough outside, your automatic
headlamp system will turn on your headlamps at the
normal brightness along with other lamps such as the
taillamps, sidemarker, parking lamps and the instrument
panel lights. The radio lights will also be dim.
Your vehicle is equipped with a light sensor on the top
of the instrument panel in the defroster grille. Be sure it
is not covered, or the system will be on whenever the
ignition is on.
The system may also turn on your headlamps when
driving through a parking garage, heavy overcast
weather or a tunnel. This is normal.
There is a delay in the transition between the daytime
and nighttime operation of the Daytime Running Lamps
(DRL) and the automatic headlamp systems so that
driving under bridges or bright overhead street lights does
not affect the system. The DRL and automatic headlamp
system will only be affected when the light sensor sees a
change in lightning lasting longer than the delay.To idle your vehicle with the automatic headlamp
system off, set the parking brake while the ignition is
off. Then start your vehicle. The automatic headlamp
system 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.Lamps On Reminder
A reminder tone will sound when your headlamps or
parking lamps are manually turned on and your ignition
is in the OFF, LOCK or ACCESSORY position. To
disable the tone, turn the thumbwheel all the way down.
In the automatic mode, the headlamps turn off once the
ignition key is in OFF.
Daytime Running Lamps
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.

2-41
The DRL system will make your headlamps come on at
a reduced brightness when:

the ignition is on,

the headlamp switch is in automatic headlamp mode.

the automatic transmission is not in PARK (P),

the light sensor determines it is daytime and

the parking brake is released.
When the DRL are on, only your DRL lamps will be on.
The taillamps, sidemarker and other lamps won't be on.
Your instrument panel won't be lit up either.
When it begins to get dark, the automatic headlamp
system will switch from DRL to the headlamps or the
last chosen headlamp setting that was used.
To idle the vehicle with the DRL off, set the parking
brake. Shifting the transmission into PARK (P) will
also allow you to idle the vehicle with the DRL off.
The DRL will stay off until you release the parking
brake or shift the transmission out of PARK (P).
As with any vehicle, you should turn on the regular
headlamp system when you need it.Interior Lamps
Instrument Panel Intensity Control
The instrument panel intensity control is located to the
right of the headlamp switch.
Turn the thumbwheel up to adjust the instrument panel
lights. To turn on the dome lamps (with the vehicle
doors closed) turn the thumbwheel all the way up.
Exit Lighting
With exit lighting, the interior lamps will come on when
you remove the key from the ignition. The lights will
not come on if the DOME OVERRIDE button is
pressed in.
Illuminated Entry
Your vehicle is equipped with an illuminated entry feature.
When the doors are opened, the dome lamps will come
on if the DOME OVERRIDE button is in the ªoutº
position. When all the doors are closed, the lamps will
stay on for a short period of time and will then go out.
If the DOME OVERRIDE button is pressed in, the
lamps will not come on.

2-62
When one of the warning lights comes on and stays on
when you are driving, or when one of the gages shows
there may be a problem, check the section that tells you
what to do about it. Please follow this manual's advice.
Waiting to do repairs can be costly
-- and even
dangerous. So please get to know your warning lights
and gages. They're a big help.
Safety Belt Reminder Light
When the key is turned to RUN or START, a tone will
come on for about eight seconds to remind people to
fasten their safety belts, unless the driver's safety belt is
already buckled.
The safety belt light will
also come on and stay on
for about 20 seconds,
then it will flash for
about 55 seconds.
If the driver's belt is already buckled, neither the tone
nor the light will come on.
Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows AIR BAG. The system checks the
air bag's electrical system for malfunctions. The light
tells you if there is an electrical problem. The system
check includes the air bag sensor, the air bag modules,
the wiring and the crash sensing and diagnostic module.
For more information on the air bag system, see ªAir
Bagº in the Index.
This light will come on
when you start your vehicle,
and it will flash for a few
seconds. Then the light
should go out. This means
the system is ready.
If the air bag readiness light stays on after you start the
vehicle or comes on when you are driving, your air bag
system may not work properly. Have your vehicle
serviced right away.

6-66
Fuse/Circuit
Breaker Usage
ECM
-B Fuel Pump Relay and Motor,
VCM, Oil Pressure
Switch/Sender
HORN Horn Relay and Horn
A/C COMP A/C Enable Relay
and Compressor
RR HTR/AC Rear Heater and A/C
ATC Active Transfer Case
FRT HVAC Front Heater and A/C
ENG
-I Oxygen Sensors, Camshaft
Position Sensor, Mass Air Flow
Sensor, Evaporative Emission
Canister Vent Solenoid
IGN
-E A/C Enable Relay Coil
ECM
-I Fuel Injectors 1-6, Crankshaft
Position Sensor, VCM, Coil
Driver Module (EST),
Ignition CoilFuse/Circuit
Breaker Usage
RH HDLMP Right Headlamp
LH Headlamp Left Headlamp
DIODE
-A/C Coil A/C
LIGHTING Courtesy Fuse, Pwr. Adj.
Mirrors Fuse, TBC
-Battery Fuse
BATT Power ACCY CB, Stop/Hazard
Fuse, Auxiliary Power Fuse,
Cigarette Lighter Fuse,
Radio Battery Fuse
IGN A Starter Relay, Ignition Switch
IGN B Ignition Switch
ABS Electronic Brake
Control Module
RAP Radio Accy, Power Windows
HTD MIR/RR
DEFOGRear Window Defogger,
HVAC Control Head
*A fuse puller is included in the underhood electrical
center. You will also find spare fuses.