1999 GMC SONOMA light

6-50 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 20 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.

6-60
GM Vehicle Care/Appearance Materials
PART NUMBERSIZEDESCRIPTIONUSAGE
99495423 in. x 25 in.Polishing Cloth ± Wax TreatedExterior polishing cloth
105017216 oz. (0.473 L)Tar and Road Oil RemoverRemoves tar, road oil and asphalt
105017316 oz. (0.473 L)Chrome Cleaner and PolishUse on chrome, stainless steel, nickel, copper and brass
105017416 oz. (0.473 L)White Sidewall Tire CleanerRemoves soil and black marks from whitewalls
105021432 oz. (0.946 L)Vinyl CleanerCleans vinyl tops, upholstery and convertible tops
105042723 oz. (0.680 L)Glass CleanerRemoves dirt, grime, smoke and fingerprints
1052918**8 oz. (0.237 L)Armor All
ProtectantProtects leather, wood, acrylics, Plexiglas
, plastic,
rubber and vinyl
105292516 oz. (0.473 L)Multi-Purpose Interior Clean-
erCleans carpets, seats, interior trim, door panels
and floor mats
105292916 oz. (0.473 L)Wheel CleanerSpray on and rinse with water
10529308 oz. (0.237 L)Capture Dry Spot RemoverAttracts, absorbs and removes soils on fabric
123457212.5 sq. ft.Synthetic ChamoisShines vehicle without scratching
1234572512 oz. (0.354 L)Silicone Tire ShineSpray on tire shine
12377964*16 oz. (0.473 L)Finish EnhancerRemoves dust, fingerprints and surface contaminants
12377966*16 oz. (0.473 L)Cleaner WaxRemoves light scratches and oxidation and protects finish
12377984*16 oz. (0.473 L)Surface CleanerRemoves contaminants, blemishes and swirl marks
See your General Motors Parts Department for these products. * For exterior use only.
See ªRecommended Fluids and Lubricantsº in the Index. ** Not recommended for use on instrument panels.

6-62
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 an internal circuit
breaker. An electrical overload will cause the lamps to go
on and off, or in some cases to remain 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.
Fuses and Circuit Breakers
The wiring circuits in your vehicle are protected from
short circuits by a combination of fuses and circuit
breakers. 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.

6-63 Instrument Panel Fuse Block
The instrument panel fuse
block is at the driver's end
of the instrument panel.
Remove the cover by turning the fastener
counterclockwise. Extra fuses and the fuse extractor are
provided in the cover. To reinstall the fuse panel cover,
push in and turn the fastener clockwise.
Fuse/Circuit
Breaker Usage
A Not Used
B Not Used
1 Not Used
2 Cigarette Lighter,
Data Link Connector
(Continued)

7-43 At Least Twice a Year
Restraint System Check
Make sure the safety belt reminder light and all your
belts, buckles, latch plates, retractors and anchorages are
working properly. Look for any other loose or damaged
safety belt system parts. If you see anything that might
keep a safety belt system from doing its job, have it
repaired. Have any torn or frayed safety belts replaced.
Also look for any opened or broken air bag coverings,
and have them repaired or replaced. (The air bag system
does not need regular maintenance.)
Wiper Blade Check
Inspect wiper blades for wear or cracking. Replace blade
inserts that appear worn or damaged or that streak or
miss areas of the windshield. Also see ªWiper Blades,
Cleaningº in the Index.Spare Tire Check
At least twice a year, after the monthly inflation check
of the spare tire determines that the spare is inflated to
the correct tire inflation pressure, make sure that the
spare tire is stored securely. Push, pull, and then try to
rotate or turn the tire. If it moves, use the wheel wrench
to tighten the cable. See ªStoring the Spare Tire and
Toolsº in the Index.
Weatherstrip Lubrication
Silicone grease on weatherstrips will make them last
longer, seal better, and not stick or squeak. Apply
silicone grease with a clean cloth. During very cold,
damp weather more frequent application may be
required. (See ªRecommended Fluids and Lubricantsº in
the Index.)
Manual Transmission Check
Check the transmission fluid level; add if needed. See
ªManual Transmission Fluidº in the Index. Check for
leaks. A fluid leak is the only reason for fluid loss. Have
the system inspected and repaired if needed.

8-6
Roadside Assistance
GMC's Roadside Assistance provides stranded owners
with over
-the-phone roadside repairs, location of the
nearest GMC dealer or the following special services:
Flat Tire Change: Installation of spare tire will be
covered at no charge (customer is responsible for repair
or replacement of tire).Fuel Delivery: Delivery of enough fuel for the customer
to get to the nearest service station (up to $4.00) will
be covered.
Jump Start: No
-start situations which require a battery
jump start will be covered at no charge.
Lock Out: Replacement keys or locksmith service will
be covered at no charge if you are unable to gain entry
into your vehicle. Delivery of the replacement key will
be covered at no charge within 10 miles (16 km).
Emergency Towing Service: Towing to the nearest
GMC dealer for warranty related disablements will
be covered.
Deluxe Trip Routing: Custom
-made, computerized
highlighted maps using the most direct or scenic route
are provided free of charge. Maps include points of
interest and a list of GMC dealers along the route. Also
included is a list of hotels along the route that are
discounted through affiliation with ªQuest
International.º Trip Routing is available through
Roadside Assistance by calling 1
-800-GMC-8782
(462-8782). Please be prepared to provide your Vehicle
Identification Number (VIN). Allow five working days
for fulfillment.

8-7
Trip Interruption Assistance: GMC will reimburse any
reasonable trip interruption expenses (up to $500.00)
when directly associated with warranty disablement. Trip
Interruption service covers expenses such as meals and
overnight lodging if vehicle disablement occurs at least
150 miles (240 km) from your home or rental property.
Please Note: you will be required to obtain prior
approval from GMC Roadside Assistance and pay for
expenses at the time of disablement. Original receipts
should be submitted to GMC Roadside Assistance for
reimbursement. A service representative will provide
assistance when you call.
The Roadside Assistance services listed are available
to retail and retail lease customers operating 2000 GMC
light duty trucks for a period of 3 years/36,000 miles
(60 000 km). All services must be pre
-arranged by
GMC Roadside Assistance.
Over
-the-phone assistance, such as providing the name
of the closest dealer or minor technical advice, etc., is
available to all owner/operators of GMC trucks,
regardless of vehicle or mileage.
Just dial GMC Roadside Assistance at
1
-800-GMC-8782 (1-800-462-8782, Roadside
Assistance prompt) to reach a qualified representative
who can assist you.Your Roadside Assistance representative will ask for the
following information when your call is received:

Vehicle Identification Number (VIN)

Name and home address

Telephone number and location from which you
are calling

Location, license plate number and color of your
GMC truck

Mileage of vehicle and description of problem
Roadside Assistance is available 24 hours a day, 7 days
a week, 365 days a year, including weekends and
holidays. Should you have any questions about roadside
assistance, call the GMC Roadside Assistance Center or
contact your dealer.
Roadside Assistance is not part of or included in the
coverage provided by the New Vehicle Limited Warranty.
GMC reserves the right to make any changes or
discontinue the Roadside Assistance program at any
time without notification.
Canadian Roadside Assistance
Vehicles purchased in Canada have an extensive
Roadside Assistance program accessible from anywhere
in Canada or the United States. Please refer to the
separate brochure provided by the dealer or call
1
-800-268-6800 for emergency services.

8-13
PUBLICATION FORM
NUMBEROrders will be mailed within 10 days of receipt. Please allow adequate time for postal
service. If further information is needed, write to the address shown below or call
1-800-551-4123. Material cannot be returned for credit without packing slip with return
information within 30 days of delivery. On returns, a re-stocking fee may be applied
against the original order. ORDER TOLL FREE
(NOTE: For Credit Card Holders Only)1-800-551-4123(Monday-Friday 8:00 AM ± 6:00 PM EST)
FAX Orders Only 1-313-865-5927
Service Manual
NOTE: Dealers and Companies please provide dealer or company name, and also the
name of the person to whose attention the shipment should be sent.
Mail completed order form to:
HELM, INCORPORATED
P.O. Box 07130
Detroit, MI 48207
For purchases outside U.S.A. please write to the above address for quotation.
2000$120.00
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2000
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TOTAL MATERIAL
Michigan Purchasers
U.S. Order Processing$6.00
Canadian Postage
GRAND TOTAL
add 6% sales tax
(See Note Below)
GM-GMC-ORD99 *(Prices are subject to change without notice and without incurring
obligation. Allow ample time for delivery.)Note to Canadian Customers: All listed prices are quoted in U.S. funds. Canadian residents
are to make checks payable in U.S. funds. To cover Canadian postage, add $11.50 plus the
U.S. order processing.
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