2002 GMC ENVOY brake sensor

1-29
In many crashes severe enough to inflate an air bag,
windshields are broken by vehicle deformation.
Additional windshield breakage may also occur from
the right front passenger air bag.

Air bags are designed to inflate only once. After an
air bag inflates, you'll need some new parts for your
air bag system. If you don't get them, the air bag
system won't be there to help protect you in another
crash. A new system will include air bag modules
and possibly other parts. The service manual for
your vehicle covers the need to replace other parts.

Your vehicle is equipped with an electronic frontal
sensor, which helps the sensing system distinguish
between a moderate frontal impact and a more
severe frontal impact. Your vehicle is also equipped
with a crash sensing and diagnostic module, which
records information about the frontal air bag system.
The module records information about the readiness
of the system, when the system commands air bag
inflation and driver's safety belt usage at deployment.
The module also records speed, engine rpm, brake
and throttle data.

Let only qualified technicians work on your air
bag systems. Improper service can mean that an
air bag system won't work properly. See your dealer
for service.
NOTICE:
If you damage the covering for the driver's
or the right front passenger's air bag, or the
air bag covering on the driver's and right front
passenger's seatback, the bag may not work
properly. You may have to replace the air bag
module in the steering wheel, both the air bag
module and the instrument panel for the right
front passenger's air bag, or both the air bag
module and seatback for the driver's and right
front passenger's side impact air bag. Do not
open or break the air bag coverings.

2-47
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 lighting 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,
or until you shift out of park.
You may be able to turn off your automatic headlamp
system. See ªDaytime Running Lamps (DRL)º later in
this section for more information.
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, the driver's door
is open and your ignition is in LOCK or ACCESSORY.
To turn the tone off, turn the knob all the way
counterclockwise. In the automatic mode, the headlamps
turn off once the ignition key is in LOCK.
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. Fully
functional daytime running lamps are required on all
vehicles first sold in Canada.
The DRL system will make your headlamps come
on at reduced brightness when the following conditions
are met:

The ignition is on,

the exterior lamps knob is in automatic
headlamp mode,

the light sensor detects daytime light, and

the transmission is not in PARK (P).
When the DRL are on, only your headlamps will be on.
The taillamps, sidemarker and other lamps won't be on.
The instrument panel won't be lit up either.
When it begins to get dark, the headlamps
will automatically switch from DRL to the
regular headlamps.

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