AC system GMC SIERRA 2001 Owner's Manual

6-40
Checking Brake Fluid
You can check the brake fluid without taking off the cap.
Just look at the brake fluid reservoir. The fluid level
should be above MIN. If it isn't, have your brake
system checked to see if there is a leak.
After work is done on the brake hydraulic system,
make sure the level is above the MIN but not over
the MAX mark.What to Add
When you do need brake fluid, use only DOT
-3 brake
fluid. Refer to ªRecommended Fluids and Lubricantsº
in the Index. Use new brake fluid from a sealed
container only.
Always clean the brake fluid reservoir cap and the area
around the cap before removing it. This will help keep
dirt from entering the reservoir.
CAUTION:
With the wrong kind of fluid in your brake
system, your brakes may not work well, or they
may not even work at all. This could cause a
crash. Always use the proper brake fluid.

6-41
NOTICE:

Using the wrong fluid can badly damage
brake system parts. For example, just a few
drops of mineral
-based oil, such as engine
oil, in your brake system can damage brake
system parts so badly that they'll have to
be replaced. Don't let someone put in the
wrong kind of fluid.

If you spill brake fluid on your vehicle's
painted surfaces, the paint finish can be
damaged. Be careful not to spill brake
fluid on your vehicle. If you do, wash it off
immediately. See ªAppearance Careº in
the Index.
Brake Wear
Your vehicle has four-wheel disc brakes.
Disc brake pads have built
-in wear indicators that make
a high
-pitched warning sound when the brake pads are
worn and new pads are needed. The sound may come
and go or be heard all the time your vehicle is moving
(except when you are pushing on the brake pedal firmly).
CAUTION:
The brake wear warning sound means that soon
your brakes won't work well. That could lead to
an accident. When you hear the brake wear
warning sound, have your vehicle serviced.

6-42
NOTICE:
Continuing to drive with worn-out brake pads
could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheel nuts are necessary to help prevent
brake pulsation. When tires are rotated, inspect brake
pads for wear and evenly tighten wheel nuts in the proper
sequence to GM torque specifications.
Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7 of this
manual under Part C ªPeriodic Maintenance Inspections.º
Brake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in pedal
travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you make a brake stop, your disc brakes
adjust for wear.
Replacing Brake System Parts
The braking system on a vehicle is complex. Its many
parts have to be of top quality and work well together
if the vehicle is to have really good braking. Your
vehicle was designed and tested with top
-quality
GM brake parts. When you replace parts of your braking
system
-- for example, when your brake linings wear
down and you have to have new ones put in
-- be sure
you get new approved GM replacement parts. If you
don't, your brakes may no longer work properly.
For example, if someone puts in brake linings that
are wrong for your vehicle, the balance between your
front and rear brakes can change
-- for the worse.
The braking performance you've come to expect can
change in many other ways if someone puts in the
wrong replacement brake parts.

6-43
Battery
Your new vehicle comes with a maintenance free
ACDelco
battery. When it's time for a new battery,
get one that has the replacement number shown on the
original battery's label. We recommend an ACDelco
battery. See ªEngine Compartment Overviewº in the
Index for battery location.
WARNING: Battery posts, terminals and related
accessories contain lead and lead compounds, chemicals
known to the State of California to cause cancer and
reproductive harm. Wash hands after handling.
Vehicle Storage
If you're not going to drive your vehicle for 25 days or
more, remove the black, negative (
-) cable from the battery.
This will help keep your battery from running down.
CAUTION:
Batteries have acid that can burn you and gas that
can explode. You can be badly hurt if you aren't
careful. See ªJump Startingº in the Index for tips
on working around a battery without getting hurt.
Contact your dealer to learn how to prepare your vehicle
for longer storage periods.
Also, for your audio system, see ªTheft
-Deterrent
Featureº in the Index.
Bulb Replacement
For any bulb changing procedure not listed in this
section, contact your GM dealership service department.
Before you replace any bulbs, be sure that all the lamps
are off and the engine isn't running. See ªReplacement
Bulbsº in the Index for the proper types of bulbs to use.
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.

6-58 Uniform Tire Quality Grading
Quality grades can be found where applicable on the
tire sidewall between tread shoulder and maximum
section width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance.
(This applies only to vehicles sold in the United States.)
The grades are molded on the sidewalls of most
passenger car tires. The Uniform Tire Quality Grading
system does not apply to deep tread, winter
-type snow
tires, space
-saver or temporary use spare tires, tires with
nominal rim diameters of 10 to 12 inches (25 to 30 cm),
or to some limited
-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specified government test course.
For example, a tire graded 150 would wear one and
a half (1 1/2) times as well on the government course
as a tire graded 100. The relative performance of
tires depends upon the actual conditions of their use,
however, and may depart significantly from the norm
due to variations in driving habits, service practices and
differences in road characteristics and climate.
Traction
-- AA, A, B, C
The traction grades, from highest to lowest, are AA,
A, B, and C. Those grades represent the tire's ability
to stop on wet pavement as measured under controlled
conditions on specified government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight
-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.

6-68
Sheet Metal Damage
If your vehicle is damaged and requires sheet metal
repair or replacement, make sure the body repair shop
applies anti
-corrosion material to the parts repaired or
replaced to restore corrosion protection.
Original manufacturer replacement parts will provide
the corrosion protection while maintaining the warranty.
Finish Damage
Any stone chips, fractures or deep scratches in the finish
should be repaired right away. Bare metal will corrode
quickly and may develop into a major repair expense.
Minor chips and scratches can be repaired with touch
-up
materials available from your dealer or other service
outlets. Larger areas of finish damage can be corrected
in your dealer's body and paint shop.
Underbody Maintenance
Chemicals used for ice and snow removal and dust
control can collect on the underbody. If these are
not removed, accelerated corrosion (rust) can occur
on the underbody parts such as fuel lines, frame,
floor pan and exhaust system even though they have
corrosion protection.At least every spring, flush these materials from the
underbody with plain water. Clean any areas where mud
and other debris can collect. Dirt packed in closed areas
of the frame should be loosened before being flushed.
Your dealer or an underbody car washing system can
do this for you.
Chemical Paint Spotting
Some weather and atmospheric conditions can create
a chemical fallout. Airborne pollutants can fall upon
and attack painted surfaces on your vehicle. This
damage can take two forms: blotchy, ringlet
-shaped
discolorations, and small irregular dark spots etched
into the paint surface.
Although no defect in the paint job causes this,
GM will repair, at no charge to the owner, the surfaces
of new vehicles damaged by this fallout condition
within 12 months or 12,000 miles (20 000 km) of
purchase, whichever occurs first.
This applies only to materials manufactured and sold by
General Motors. Bodies, body conversions or equipment
not made or sold by General Motors are not covered.

6-71
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.
Windshield Wipers
The windshield wiper motor is protected by an internal
circuit breaker and a fuse. If the motor overheats due
to heavy snow, etc., the wiper will stop until the motor
cools. If the overload is caused by some electrical
problem and not snow, etc., 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.
Fuses and Circuit Breakers
The wiring circuits in your vehicle are protected from
short circuits by a combination of fuses, circuit breakers
and fusible thermal links. This greatly reduces the
chance of fires caused by electrical problems.
Look at the silver
-colored band inside the fuse. If the
band is broken or melted, replace the fuse. Be sure you
replace a bad fuse with a new one of the identical size
and rating.
If you ever have a problem on the road and don't have
a spare fuse, you can borrow one that has the same
amperage. Just pick some feature of your vehicle that
you can get along without
-- like the radio or cigarette
lighter
-- and use its fuse, if it is the correct amperage.
Replace it as soon as you can.

6-72
Instrument Panel Fuse Block
The fuse block access door
is on the driver's side edge
of the instrument panel.
Pull off the cover to access
the fuse block.
You can remove fuses with a fuse extractor which is
mounted to the fuse block access door. To remove fuses
if you don't have a fuse extractor, hold the end of the
fuse between your thumb and index finger and pull
straight out.
You may have spare fuses located behind the fuse block
access door. These can be used to replace a bad fuse.
However, make sure it is of the correct amperage.
NAME Usage
L BODY Retained Accessory Power Relay
LOCK Power Door Locks
DRV UNLOCK Power Door Lock Relay
LOCK Power Door Lock Relay
HVAC 1 Climate Control System

6-73
NAME Usage
CRUISE Cruise Control, Instrument
Panel Cluster
IGN 3 Ignition, Power Seats
4WD Four
-Wheel Drive System,
Auxiliary Battery
CRANK Starting System
INT PRK Parking Lamps, Sidemarker Lamps,
Interior Lamps
L DOOR Power Door Lock Relay
BRAKE Anti
-Lock Brake System
RR WIPER Not Used
ILLUM Interior Lamps
SEAT Power Seat Circuit Breaker
TURN Exterior Lamps, Turn Signals,
Hazard Lamps
UNLOCK Power Door LocksNAME Usage
HTR A/C Climate Control System
WS WPR Windshield Wipers
IGN 1 Ignition, Instrument Panel
AIR BAG Air Bag
MIR/LOCK Power Mirrors, Power Door Locks
DR LOCK Power Door Locks
PWR WDO Power Window Circuit Breaker
UNLOCK Power Door Lock Relay
IGN 0 PRND321 Display, Odometer, PCM
SEO IGN Special Equipment Option,
Ignition, Manual Selectable Ride
SEO ACCY Special Equipment Option
Accessory, Cellular Telephone
RAP #1 Retained Accessory Power Relay
RDO 1 Audio System
RAP #2 Not Used

6-77
*1 INJ B--Gasoline Engine and Diesel Engine.
*2 ECM I
--Gasoline Engine; ECMRPV--Diesel Engine.
*3 02 A
--Gasoline Engine; FUEL HT--Diesel Engine.
*4 02 B
--Gasoline Engine; ECM I--Diesel Engine.
Name Usage
GLOW PLUG Diesel Glow Plugs and
Intake Air Heater
CUST FEED Gasoline Accessory Power
STUD #1Accessory Power/Trailer
Wiring Feed
ABS Anti
-Lock Brakes
IGN A Ignition Switch
AIR A.I.R. System
RAP #1 Retained Accessory Power,
Power Mirrors, Power Door Locks,
Power Seat(s)
IGN B Ignition Switch
RAP #2 Not Used
STUD #2 Accessory Power/Trailer Wiring
Brake Feed
SPARE Spare FuseName Usage
TRL R TRN Right Turn Signal Trailer Wiring
TRL L TRN Left Turn Signal Trailer Wiring
IGN 1 Ignition, Fuel Controls (Relay)
INJ B Ignition, Fuel Controls
STARTER Starter (Relay)
PARK LP Parking Lamps
FRT HVAC Climate Control System
STOP LP Exterior Lamps, Stoplamps
ECM I PCM
ECMRPV Fuel Controls, ECM
CHMSL Center High Mounted Stoplamp
VEH STOP Stoplamps, Cruise Control
TRL B/U Backup Lamps Trailer Wiring
INJ A Fuel Controls, Ignition
RR HVAC Not Used
VEH B/U Vehicle Backup Lamps
ENG 1 Engine Controls, Canister Purge,
Fuel System