ignition GMC YUKON 2000 Repair Manual

4-45 Four-Wheel-Drive Vehicles
CAUTION:
Shifting the transfer case into NEUTRAL (N) can
cause your vehicle to roll even if the transmission
is in PARK (P), for an automatic transmission.
You or others could be injured. Make sure the
parking brake is firmly set before you shift the
transfer case into NEUTRAL (N).

Firmly set the parking brake.

Shift the transmission to PARK (P).
Securely attach the vehicle being towed to
the tow vehicle.

Shift the transfer case to NEUTRAL (N).
See ªFour
-Wheel Driveº in the Index for
the proper procedure to select the NEUTRAL
position for your vehicle.

Release the parking brake only after the
vehicle being towed is firmly attached to the
towing vehicle.

Turn the ignition to OFF. The OFF position
unlocks the steering column and reduces battery
drain as long as the IGN 0 fuse is removed.
Unlocking the steering column will allow the
proper movement of the front wheels and tires
during towing.

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 the transmission in
PARK (P). If you have a four
-wheel-drive vehicle,
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. In addition,
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.
CAUTION:
An electric fan can start up even when the engine
is not running and can injure you. Keep hands,
clothing and tools away from any underhood
electric fan.

5-21
Follow these instructions to lower the spare tire:
1. If the vehicle is equipped with a hoist lock, open
the spare tire lock cover on the bumper and use the
ignition key to remove the lock.
2. Assemble the wheel wrench and the two jack handle
extensions as shown. Insert the hoist end (open end)
of the extension through the hole in the rear bumper.
Be sure the hoist end of the extension connects into
the hoist shaft (the ribbed square end of the
extension is used to lower the spare tire).
3. Turn the wheel wrench counterclockwise to lower
the spare tire to the ground. Continue to turn the
wheel wrench until the spare tire can be pulled out
from under the vehicle. The wheel wrench has a
hook that allows you to pull the hoist cable towards
you, to assist in reaching the spare tire.
4. When the tire has been lowered, tilt the retainer at
the end of the cable so it can be pulled up through
the wheel opening.
5. Put the spare tire near the flat tire.
The tools you'll be using include the bottle jack (A), the
wheel blocks (B), the jack handle (C), the jack handle
extensions (D), and the wheel wrench (E).
If the flat tire is on the rear of the vehicle, you'll need
to use both jack handle extensions.

6-14
How to Reset the CHANGE ENGINE OIL Message
To reset the CHANGE ENGINE OIL message, turn
the ignition key to RUN with the engine off. Fully press
and release the accelerator pedal three times within five
seconds. If the CHANGE ENGINE OIL message flashes
for five seconds, the system is reset.
What to Do with Used Oil
Did you know that used engine oil contains certain
elements that may be unhealthy for your skin and could
even cause cancer? Don't let used oil stay on your skin
for very long. Clean your skin and nails with soap and
water, or a good hand cleaner. Wash or properly throw
away clothing or rags containing used engine oil. (See
the manufacturer's warnings about the use and disposal
of oil products.)
Used oil can be a real threat to the environment. If you
change your own oil, be sure to drain all free
-flowing
oil from the filter before disposal. Don't ever dispose of
oil by putting it in the trash, pouring it on the ground,
into sewers, or into streams or bodies of water. Instead,
recycle it by taking it to a place that collects used oil.
If you have a problem properly disposing of your used
oil, ask your dealer, a service station or a local recycling
center for help.
Engine Air Cleaner/Filter
The air cleaner assembly
has an indicator that lets
you know when the air
filter is dirty and needs to
be serviced. The indicator
is located on the air
cleaner cover.
See ªOwner Checks and Servicesº in the Index to
determine when to check the indicator.
If the area inside the clear section of the indicator is
not completely yellow, no air filter service is required.
When the area inside the indicator is completely yellow,
past the red band, the words ªCHANGE FILTERº will
be highlighted. After changing the air filter, press the top
button on the indicator to reset it.

6-57
NAME Usage
LOCK Power Door Lock Relay
HVAC 1 Climate Control System
CRUISE Cruise Control, Instrument 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 Rear Window Wiper
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,
VCM/PCM
SEO IGN Special Equipment Option,
Ignition
SEO ACCY Special Equipment Option
Accessory, Cellular Telephone
RAP #1 Retained Accessory Power Relay
RDO 1 Audio System
RAP #2 Rear Power Windows,
Sunroof, Radio

6-61
Name Usage
STUD #1 Accessory Power/Trailer
Wiring Feed/Load Leveling
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 Retained Accessory Power/Rear
Power Windows, Sunroof, Radio
STUD #2 Accessory Power/Trailer Wiring
Brake Feed
TRL R TRN Right Turn Signal Trailer Wiring
TRL L TRN Left Turn Signal Trailer Wiring
IGN 1 Ignition, Fuel Controls
INJ B Ignition, Fuel Controls (Relay)
STARTER Starter (Relay)
PARK LP Parking LampsName Usage
FRT HVAC Climate Control System
STOP LP Exterior Lamps, Stoplamps
ECM 1 VCM/PCM
CHMSL Center High Mounted Stoplamp
VEH STOP Stoplamps, Cruise Control
TRL B/U Backup Lamps Trailer Wiring
INJ A Fuel Controls, Ignition
RR HVAC Rear HVAC
VEH B/U Vehicle Backup Lamps
ENG 1 Engine Controls, Canister Purge,
Fuel System
ETC Electronic Throttle Control
IGN E A/C Compressor Relay, Rear
Window Defogger, Daytime
Running Lamps, A.I.R. System
B/U LP Backup Lamps, Automatic
Transmission Shift Lock
Control System
ATC Automatic Transfer Case

6-63
Name Usage
FR PRK Front Parking Lamps,
Sidemarker Lamps
W/W PMP Windshield Washer Pump
HORN Horn (Relay)
IGN C Ignition Switch, Fuel Pump,
PRND321 Display, Crank
RDO AMP Radio Amplifier
HAZ LP Exterior Lamps, Hazard Lamps
EXP LPS Not Used
HORN Horn
CTSY LP Interior Lamps
RR WPR Rear Wipers
TBC Body Control Module, Remote
Keyless Entry, HeadlampsReplacement Bulbs*
Low-Beam Headlamps2 9006
High
-Beam Headlamps2 9005
Daytime Running
Lamps (DRL)2 3157K
X
Front Marker Lamp 2 194
Front Parking and
Turn Lamp2 3157N
A
Rear Marker Lamp,
Taillamp and Stop Lamp2 3157
Rear Turn Lamp 2 3157
Back
-up Lamp2 3157
* For replacement bulbs not listed here, please consult
your dealer.

7-20
Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn
the ignition key to LOCK in each shift lever position.

The key should turn to LOCK only when the shift
lever is in PARK (P).

The key should come out only in LOCK.
Parking Brake and Automatic Transmission
PARK (P) Mechanism Check
CAUTION:
When you are doing this check, your vehicle
could begin to move. You or others could be
injured and property could be damaged. Make
sure there is room in front of your vehicle in case
it begins to roll. Be ready to apply the regular
brake at once should the vehicle begin to move.
Park on a fairly steep hill, with the vehicle facing
downhill. Keeping your foot on the regular brake,
set the parking brake.

To check the parking brake's holding ability:
With the engine running and transmission in
NEUTRAL (N), slowly remove foot pressure
from the regular brake pedal. Do this until the
vehicle is held by the parking brake only.

To check the PARK (P) mechanism's holding
ability: With the engine running, shift to PARK (P).
Then release the parking brake followed by the
regular brake.
Underbody Flushing Service
At least every spring, use plain water to flush any
corrosive materials from the underbody. Take care to
clean thoroughly any areas where mud and other debris
can collect.