2000 GMC SONOMA engine

6-32
NOTICE:

When using concentrated washer fluid,
follow the manufacturer's instructions for
adding water.

Don't mix water with ready
-to-use washer
fluid. Water can cause the solution to freeze
and damage your washer fluid tank and
other parts of the washer system. Also,
water doesn't clean as well as washer fluid.

Fill your washer fluid tank only
three
-quarters full when it's very cold.
This allows for expansion if freezing occurs,
which could damage the tank if it is
completely full.

Don't use engine coolant (antifreeze) in
your windshield washer. It can damage
your washer system and paint.
Brakes
Brake Fluid
Your brake master cylinder reservoir is filled with
DOT
-3 brake fluid.
There are only two reasons why the brake fluid level in the
reservoir might go down. The first is that the brake fluid
goes down to an acceptable level during normal brake
lining wear. When new linings are put in, the fluid level
goes back up. The other reason is that fluid is leaking out
of the brake system. If it is, you should have your brake
system fixed, since a leak means that sooner or later your
brakes won't work well, or won't work at all.

6-33
So, it isn't a good idea to ªtop offº your brake fluid.
Adding brake fluid won't correct a leak. If you add fluid
when your linings are worn, then you'll have too much
fluid when you get new brake linings. You should add
(or remove) brake fluid, as necessary, only when work is
done on the brake hydraulic system.
CAUTION:
If you have too much brake fluid, it can spill on
the engine. The fluid will burn if the engine is
hot enough. You or others could be burned, and
your vehicle could be damaged. Add brake fluid
only when work is done on the brake
hydraulic system.
Refer to the Maintenance Schedule to determine when to
check your brake fluid. See ªPeriodic Maintenance
Inspectionsº in the Index.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.

6-34
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.
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
If you have four-wheel drive, your vehicle has
four
-wheel disc brakes. If not, your vehicle has front
disc brakes and rear drum 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).

6-37
Bulb Replacement
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 any bulb changing procedure not listed in this
section, contact your GM dealer's service department.
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
One-Piece Composite Headlamp System
1. Open the hood.
2. Remove the black retainer clips by lifting up.
3. Pull the headlamp assembly out.
4. Unplug the electrical connector.

6-61
Vehicle Identification Number (VIN)
This is the legal identifier for your vehicle. It appears on
a plate in the front corner of the instrument panel, on the
driver's side. You can see it if you look through the
windshield from outside your vehicle. The VIN also
appears on the Vehicle Certification and Service Parts
labels and the certificates of title and registration.
Engine Identification
The 8th character in your VIN is the engine code. This
code will help you identify your engine, specifications
and replacement parts.
Service Parts Identification Label
You'll find this label on the inside of the glove box.
It's very helpful if you ever need to order parts.
On this label is:

your VIN,

the model designation,

paint information and

a list of all production options and special equipment.
Be sure that this label is not removed from the vehicle.

6-64
Fuse/Circuit
Breaker Usage
3 Cruise Control, Body Controls
TBC, Cruise Module,
Cruise Switch
4 Gages, Body Controls TBC,
Instrument Panel Cluster,
B+ Power
5 Parking Lamps, Power Window
Switch, TBC, Ashtray Lamp
6 Not Used
7 Headlamp Switch, Body Controls
TBC, Headlamp Relay
8 Courtesy Lamps, Inadvertent
Power Relay
9 HVAC Control Head
10 Turn Signal
11 Instrument Panel Cluster,
Engine Controls
12 Interior IlluminationFuse/Circuit
Breaker Usage
13 Auxiliary Power
14 Power Locks
15 4WD Switch, Engine Control
(VCM, PCM, Transmission)
16 Supplemental Inflatable Restraint
17 Front Wiper
18 Not Used
19 Radio Battery
20 Not Used
21 HVAC I, HVAC Control Head,
HVAC Devices
22 Anti
-Lock Brakes
23 Rear Wiper
24 Radio, Ignition

6-65 Engine Compartment Fuse Block
The fuse block is under the hood on the driver's side of
the engine compartment.
Remove the cover by turning the fastener
counterclockwise. To reinstall the fuse panel cover, push
in and turn the fastener clockwise.Name Usage
TRL TRN Not Used
TRR TRN Not Used
TRL B/U Not Used
VEH B/U Vehicle Back
-Up Lamps
RT TURN Right Turn Signal Front
LT TURN Left Turn Signal Front
HDLP W/W Not Used
(Continued)

6-66
Name Usage
LT TRN Left Turn Signal Rear
RT TRN Right Turn Signal Rear
RR PRK Right Rear Parking Lamps
TRL PRK Not Used
LT HDLP Left Headlamp
RT HDLP Right Headlamp
FR PRK Front Parking Lamps
INT BAT I/P Fuse Block Feed
ENG I Engine Sensors/Solenoids, MAF,
CAM, PURGE, VENT
ECM B Engine Control Module, Fuel Pump
Module, Oil Pressure
ABS Anti
-Lock Brake System
ECM I Engine Control Module Injectors
BTSI Automatic Transmission Shift Lock
Control System
B/U LP Back
-Up Lamps
A/C Air Conditioning
W/W PMP Not Used
HORN Horn
IGN B Column Feed, IGN 2, 3, 4
RAP Retained Accessory Power
LD LEV Not UsedName Usage
OXYSEN Oxygen Sensor
IGN E Engine
MIR/LKS Mirrors, Door Locks
FOG LP Fog Lamps
IGN A Starting and Charging IGN 1
STUD #2 Accessory Feeds, Electric Brake
PARKLP Parking Lamps
LR PRK Left Rear Parking Lamps
IGN C Starter Solenoid, Fuel Pump,
PRNDL
HTDSEAT Not Used
HVAC HVAC System
TRCHMSL Not Used
RRDFOG Not Used
TBC Truck Body Computer
CRANK Clutch Switch, NSBU Switch
HAZLP Hazard Lamps
VECHMSL Vehicle Center High
-Mounted
Stoplamp
HTDMIR Heated Outside Mirrors
ATC Transfer Case (Four
-Wheel Drive)
STOPLP Stoplamps
RR W/W Not Used