brake light GMC YUKON 1999 User Guide

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4-22 Driving Downhill
When off-roading takes you downhill, you'll want to
consider a number of things:

How steep is the downhill? Will I be able to maintain
vehicle control?

What's the surface like? Smooth? Rough? Slippery?
Hard
-packed dirt? Gravel?

Are there hidden surface obstacles? Ruts?
Logs? Boulders?

What's at the bottom of the hill? Is there a hidden
creek bank or even a river bottom with large rocks?
If you decide you can go down a hill safely, then try to
keep your vehicle headed straight down, and use a low
gear. This way, engine drag can help your brakes and
they won't have to do all the work. Descend slowly,
keeping your vehicle under control at all times.
CAUTION:
Heavy braking when going down a hill can cause
your brakes to overheat and fade. This could
cause loss of control and a serious accident.
Apply the brakes lightly when descending a
hill and use a low gear to keep vehicle speed
under control.

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4-26
Hard packed snow and ice offer the worst tire traction.
On these surfaces, it's very easy to lose control. On wet
ice, for example, the traction is so poor that you will
have difficulty accelerating. And if you do get moving,
poor steering and difficult braking can cause you to slide
out of control.
CAUTION:
Driving on frozen lakes, ponds or rivers can be
dangerous. Underwater springs, currents under
the ice, or sudden thaws can weaken the ice. Your
vehicle could fall through the ice and you and
your passengers could drown. Drive your vehicle
on safe surfaces only.
Driving in Water
Light rain causes no special off-road driving problems.
But heavy rain can mean flash flooding, and flood
waters demand extreme caution.
Find out how deep the water is before you drive through
it. If it's deep enough to cover your wheel hubs, axles or
exhaust pipe, don't try it
-- you probably won't get
through. Also, water that deep can damage your axle
and other vehicle parts.
If the water isn't too deep, then drive through it slowly. At
fast speeds, water splashes on your ignition system and
your vehicle can stall. Stalling can also occur if you get
your tailpipe under water. And, as long as your tailpipe is
under water, you'll never be able to start your engine.
When you go through water, remember that when your
brakes get wet, it may take you longer to stop.

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4-31
Driving too fast through large water puddles or even
going through some car washes can cause problems, too.
The water may affect your brakes. Try to avoid puddles.
But if you can't, try to slow down before you hit them.
CAUTION:
Wet brakes can cause accidents. They won't work
as well in a quick stop and may cause pulling to
one side. You could lose control of the vehicle.
After driving through a large puddle of water or
a car wash, apply your brake pedal lightly until
your brakes work normally.

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4-53 When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:

Start your engine;

Shift into a gear; and

Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission fluid (don't
overfill), engine oil, axle lubricant, belt, cooling system
and brake adjustment. Each of these is covered in this
manual, and the Index will help you find them quickly.
If you're trailering, it's a good idea to review these
sections before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
Light-Duty Wiring Harness

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4-54
Additional Heavy-Duty Wiring
An eight
-wire harness is stored under the rear bumper of
your vehicle. The five
-wire light-duty harness is located
at the left hand rear inner lower quarter panel. The
additional heavy
-duty wiring is located forward of the
rear bumper and is attached to the center of the rear
crossmember or the forward vertical surface of the
platform hitch.
This harness has a 30 amp battery feed wire and no
connector, and should be wired by a qualified electrical
technician. After choosing an aftermarket mating
connector pair, have the technician attach one connector tothe eight
-wire trailer harness and the other connector to the
wiring harness on the trailer. Be sure that the wiring
harness on the trailer is strapped to the trailer's frame and
leave it loose enough so that the wiring doesn't bend or
break, but not so loose that it drags on the ground. The
technician can use the following color code chart when
connecting the wiring harness to your trailer.

Brown: Rear Lamps

Yellow: Left Stoplamp and Turn Signal

Dark Green: Right Stoplamp and Turn Signal

White (Heavy Gauge): Ground

Light Green: Back
-up Lamps

White (Light Gauge): Center High
-Mounted Stop
Lamp (If Equipped)

Blue: Auxiliary/Electric Trailer Brake Circuit
(If Equipped)

Orange: Fused Auxiliary Circuit (If Equipped)
Store the harness in its original place. Wrap the harness
together and tie it neatly so it won't be damaged.

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5-4
1. Check the other vehicle. It must have a 12-volt
battery with a negative ground system.
NOTICE:
If the other system isn't a 12-volt system with a
negative ground, both vehicles can be damaged.
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren't touching
each other. If they are, it could cause a ground
connection you don't want. You wouldn't be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on both vehicles involved in
the jump start procedure. Put an automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL (N) before setting the parking brake.
Be sure the transfer case is not in NEUTRAL (N).3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets. Turn off all lamps
that aren't needed as well as radios. This will avoid
sparks and help save both batteries. And it could
save your radio!
NOTICE:
If you leave your radio on, it could be badly
damaged. The repairs wouldn't be covered by
your warranty.

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6-31
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 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).
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.
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.

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6-59
Fuse/Circuit
BreakerUsage
15 DRL Relay, Fog Lamp Relay
16 Front and Rear Turn Signals,
Back
-Up Lamps, BTSI Solenoid
17 Radio (Ignition)
18 4WAL/VCM, ABS, Cruise Control
19 Radio (Battery)
20 PRNDL, Automatic Transmission,
Speedometer, Check Gages,
Warning Lights
21 Security/Steering
22 Auxiliary Power, Headlamp Delay
23 Rear Wiper, Rear Washer Pump
24 Front Axle, 4WD Indicator Lamp,
TP2 Relay
A Power Door Lock, Six
-Way Power
Seat, Keyless Entry Module
B Power WindowsUnderhood Fuse/Relay Center
The underhood fuse/relay center is located in the rear of
the engine compartment near the brake fluid reservoir.
Move the retainer clips for the cover to access the
fuse block.
You can remove fuses with a fuse extractor. The fuse
extractor is mounted to the interior fuse block. 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.

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6-60
Name Circuits Protected
ECM
-B Fuel Pump, PCM/VCM
RR DEFOG Rear Window Defogger
IGN
-E Auxiliary Fan Relay Coil, A/C
Compressor Relay, Hot Fuel Module
FUEL SOL Not Used
GLOW PLUG Not UsedName Circuits Protected
HORN Horn, Underhood Lamp
AUX FAN Auxiliary Fan
ECM
-1 Injectors, PCM/VCM
HTD ST
-FR Heated Front Seats
A/C Air Conditioning
HTD MIR Heated Outside Mirrors
ENG
-1 Ignition Switch, EGR, Canister
Purge, EVRV Idle Coast Solenoid,
Heated O
2
HTD ST-RR Heated Rear Seats
LIGHTING Headlamp and Panel Dimmer
Switch, Fog and Courtesy Fuses
BATT Battery, Fuse Block Busbar
IGN
-A Ignition Switch
IGN
-B Ignition Switch
ABS Anti
-Lock Brake Module
BLOWER Hi Blower and Rear Blower Relays
STOP/HAZ Stoplamps
HEATED
SEATSHeated Seats

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9-1
Section 9 Index
A
ir Bag 1-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding Equipment 1-30 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How Does it Restrain 1-27 . . . . . . . . . . . . . . . . . . . . . . . . . .
How it Works 1-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Location 1-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Readiness Light 1-25, 2-73 . . . . . . . . . . . . . . . . . . . . . . . . .
Servicing 1-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
What Makes it Inflate 1-27 . . . . . . . . . . . . . . . . . . . . . . . . . .
What Will You See After it Inflates 1-28 . . . . . . . . . . . . . . .
When Should it Inflate 1-27 . . . . . . . . . . . . . . . . . . . . . . . . .
Air Cleaner/Filter 6-15, 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Cleaner Filter Restriction Indicator Check 7-36 . . . . . . . .
Air Conditioning 3-2, 3-3, 3-4 . . . . . . . . . . . . . . . . . . . . . . . .
Air Conditioning Refrigerants 6-64 . . . . . . . . . . . . . . . . . . . . .
Alignment and Balance, Tire 6-45 . . . . . . . . . . . . . . . . . . . . . .
Aluminum Wheels, Cleaning 6-52 . . . . . . . . . . . . . . . . . . . . . .
Antenna, Fixed 3-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Antifreeze 6-23, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Anti-Lock Brake System Warning Light 2-75, 4-7 . . . . . . . . .
Anti-Lock Brakes 4-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Anti-Theft, Radio 3-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appearance Care 6-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appearance Care and Materials 6-54 . . . . . . . . . . . . . . . . . . . .
Arbitration Program 8-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ashtrays 2-61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio Equipment, Adding 3-22 . . . . . . . . . . . . . . . . . . . . . . . .
Audio Systems 3-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Automatic Headlamp System 2
-47 . . . . . . . . . . . . . . . . . . . . . .
Automatic Transmission
Check 7
-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid 6-17, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation 2-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overdrive 2-27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Park Mechanism Check 7-38 . . . . . . . . . . . . . . . . . . . . . . . .
Shifting 2-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auxiliary Power Outlet 2-62 . . . . . . . . . . . . . . . . . . . . . . . . . .
Axle, Front 6-22, 7-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Axle, Locking Rear 2-38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Axle, Rear 6-20, 7-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Battery 6-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Jump Starting 5-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacement, Keyless Entry 2-9 . . . . . . . . . . . . . . . . . . . . .
Rundown Protection 2-50 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Warnings 5-3, 5-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BBB Auto Line 8-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Better Business Bureau Mediation 8-4 . . . . . . . . . . . . . . . . . . .
Blizzard 4-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake
Adjustment 6
-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid 6-29, 7-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Master Cylinder 6-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parking 2-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pedal Travel 6-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .