headlamp GMC ENVOY 2002 Owner's Guide

4-30
Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to be
impaired
-- by alcohol or drugs, with night vision
problems, or by fatigue.Here are some tips on night driving.

Drive defensively.

Don't drink and drive.

Since you can't see as well, you may need to
slow down and keep more space between you and
other vehicles.

Slow down, especially on higher speed roads. Your
headlamps can light up only so much road ahead.

In remote areas, watch for animals.

If you're tired, pull off the road in a safe place
and rest.

4-31
No one can see as well at night as in the daytime. But as
we get older these differences increase. A 50
-year-old
driver may require at least twice as much light to see the
same thing at night as a 20
-year-old.
What you do in the daytime can also affect your night
vision. For example, if you spend the day in bright
sunshine you are wise to wear sunglasses. Your eyes
will have less trouble adjusting to night. But if you're
driving, don't wear sunglasses at night. They may cut
down on glare from headlamps, but they also make a lot
of things invisible.
You can be temporarily blinded by approaching
headlamps. It can take a second or two, or even several
seconds, for your eyes to readjust to the dark. When
you are faced with severe glare (as from a driver who
doesn't lower the high beams, or a vehicle with
misaimed headlamps), slow down a little. Avoid staring
directly into the approaching headlamps.Keep your windshield and all the glass on your vehicle
clean
-- inside and out. Glare at night is made much
worse by dirt on the glass. Even the inside of the glass
can build up a film caused by dust. Dirty glass makes
lights dazzle and flash more than clean glass would,
making the pupils of your eyes contract repeatedly.
Remember that your headlamps light up far less of a
roadway when you are in a turn or curve. Keep your
eyes moving; that way, it's easier to pick out dimly
lighted objects. Just as your headlamps should be
checked regularly for proper aim, so should your eyes
be examined regularly. Some drivers suffer from night
blindness
-- the inability to see in dim light -- and
aren't even aware of it.

4-43

Put on extra clothing or wrap a blanket around you.
If you have no blankets or extra clothing, make body
insulators from newspapers, burlap bags, rags, floor
mats
-- anything you can wrap around yourself or
tuck under your clothing to keep warm.
You can run the engine to keep warm, but be careful.
CAUTION:
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill
you. You can't see it or smell it, so you might not
know it is in your vehicle. Clear away snow from
around the base of your vehicle, especially any
that is blocking your exhaust pipe. And check
around again from time to time to be sure snow
doesn't collect there.
Open a window just a little on the side of the
vehicle that's away from the wind. This will help
keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little faster
than just idle. That is, push the accelerator slightly. This
uses less fuel for the heat that you get and it keeps the
battery charged. You will need a well
-charged battery to
restart the vehicle, and possibly for signaling later on
with your headlamps. Let the heater run for a while.

6-34 Halogen Bulbs
CAUTION:
Halogen bulbs have pressurized gas inside and
can burst if you drop or scratch the bulb. You or
others could be injured. Be sure to read and
follow the instructions on the bulb package.
Headlamps
1. Open the hood.
2. Lift the inner quick release clips.
3. Pull the headlamp assembly away from the vehicle.
4. Remove the cover from the headlamp bulb.
5. Disconnect the wiring harness.
6. Remove the headlamp bulb by turning the socket
counterclockwise.
7. To install the replacement bulb, reverse
Steps 1 through 6.
Front Turn Signals and Sidemarker Lamps
Follow the same procedure listed for headlamp removal
earlier in this section. Replace the turn signal or
sidemarker bulb instead.
Taillamps and Rear Turn Signals
1. Open the liftgate.
2. Remove the two screws
from the lamp assembly.
3. Pull the assembly away from the vehicle.

6-45
Each new wheel should have the same load-carrying
capacity, diameter, width, offset and be mounted the
same way as the one it replaces.
If you need to replace any of your wheels, wheel bolts
or wheel nuts, replace them only with new GM original
equipment parts. This way, you will be sure to have the
right wheel, wheel bolts and wheel nuts for your vehicle.
CAUTION:
Using the wrong replacement wheels, wheel bolts
or wheel nuts on your vehicle can be dangerous.
It could affect the braking and handling of your
vehicle, make your tires lose air and make
you lose control. You could have a collision in
which you or others could be injured. Always
use the correct wheel, wheel bolts and wheel nuts
for replacement.
NOTICE:
The wrong wheel can also cause problems with
bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper
height, vehicle ground clearance and tire or tire
chain clearance to the body and chassis.
See ªChanging a Flat Tireº in the Index for
more information.
Used Replacement Wheels
CAUTION:
Putting a used wheel on your vehicle is
dangerous. You can't know how it's been used or
how far it's been driven. It could fail suddenly
and cause a crash. If you have to replace a wheel,
use a new GM original equipment wheel.

6-56
Electrical System
Add-On Electrical Equipment
NOTICE:
Don't add anything electrical to your vehicle
unless you check with your dealer first. Some
electrical equipment can damage your vehicle
and the damage wouldn't be covered by your
warranty. Some add
-on electrical equipment
can keep other components from working as
they should.
Your vehicle has an air bag system. Before attempting to
add anything electrical to your vehicle, see ªServicing
Your Air Bag
-Equipped Vehicleº in the Index.
Headlamps
The headlamp wiring is protected by four fuses. An
electrical overload will cause a lamp to go on and off.
If this happens, have your headlamp wiring checked
right away.
Windshield Wipers
The windshield wiper motor is protected by a circuit
breaker and a fuse. If the motor overheats due to heavy
snow or ice, the wiper will stop until the motor cools. If
the overload is caused by some electrical problem, be
sure to get it fixed.
Power Windows and Other Power Options
Circuit breakers protect the power windows and other
power accessories. When the current load is too heavy,
the circuit breaker opens and closes, protecting the
circuit until the problem is fixed or goes away.

6-59
Mini Fuses Usage
1 ECAS
2 Passenger's Side
High
-Beam Headlamp
3 Passenger's Side
Low
-Beam Headlamp
4 Back
-Up Trailer Lamps
5 Driver's Side
High
-Beam Headlamp
6 Driver's Side
Low
-Beam Headlamp
7 WASH
8ATC
9 Windshield Wipers
10 Powertrain Control Module B
11 Fog Lamps
12 ST/LP
13 Cigarette Lighter
14 COILSMini Fuses Usage
15 RIDE
16 TBD
-- Ignition 1
17 Crank
18 Air Bag
19 ELEK Brake
20 Cooling Fan
21 Horn
22 Ignition E
23 ETC
24 Instrument Panel Cluster,
Driver Information Center
25 Automatic Shift Lock
Control System
26 ENG 1
27 Back
-Up
28 Powertrain Control Module 1
29 Oxygen Sensor

6-60
Mini Fuses Usage
30 Air Conditioning
31 TBC
50 Passenger's Side Trailer TRN
51 Driver's Side Trailer TRN
52 Hazard Flashers
J
-Case Fuses Usage
32 Trailer
33 Anti
-Lock Brakes (ABS)
34 Ignition A
35 Blower Motor
36 Ignition B
Micro Relays Usage
37 Headlamp Washer
38 Rear Window Washer
39 Fog LampsMicro Relays Usage
40 Horn
41 Fuel Pump
42 Windshield Wipers/Washer
43 High
-Beam Headlamp
44 Air Conditioning
Solid State
RelaysUsage
45 Cooling Fan
46 HDM
Mini Relay Usage
47 Starter
Miscellaneous Usage
48 Instrument Panel Battery
49 Fuse Puller

6-63
Fuse Usage
35 Blank
36 HVAC B
37 Front Parking Lamps
38 Left Turn Signal
39 HVAC 1
40 TBC 4
41 Radio
42 TR PARK
43 Right Turn Signal
44 HVAC
45 Rear Fog Lamps
46 Auxiliary Power 1
47 Ignition 0
48 Four
-Wheel Drive
49 Blank
50 TBC IG
51 Brakes
52 TBC RUN
Replacement Bulbs
Lamps Number
Halogen Headlamps
Low Beam 9006 HB4. . . . . . . . . . . . . . . . . . . . . . . .
High Beam 9005 HB3. . . . . . . . . . . . . . . . . . . . . . .
Front Sidemarker Lamps 194. . . . . . . . . . . . . . . . . . .
Front Turn Signal Lamps 3457. . . . . . . . . . . . . . . . . .
Tail and Stoplamps 3057. . . . . . . . . . . . . . . . . . . . . . .
Rear Turn Signal Lamps 3057. . . . . . . . . . . . . . . . . .
For any bulb not listed here contact your dealer.
Capacities and Specifications
Engine Specifications
Engine Description ªVORTECº 4200. . . . . . . . . . . .
Type L6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VIN Code S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Firing Order 1
-5-3-6-2-4 . . . . . . . . . . . . . . . . . . . . . .
Spark Plug Gap 0.050 inches (1.25 mm). . . . . . . . . .