2002 GMC YUKON XL DENALI lock

6-64
Center Instrument Panel Utility Block
The center instrument panel utility block is located
underneath the instrument panel, to the left of the
steering column.Relay Name Usage
SEO Special Equipment Option
TRAILER Trailer Brake Wiring
UPF Upfitter
SPARE 2 Not Used
SPARE 3 Not Used
HTD ST Heated Seats
PWR ST Power Seats
PARK LAMP Parking Lamps
INADV PWR Interior Lamps Feed
SPARE Not Used
SPARE Not Used
*FRT PRK EXPT Not Used
PUDDLE LP Puddle Lamps
CTSY LP Courtesy Lamps
VANITY Headliner Wiring
BLANK Not Used
SL RIDE Not Used
CEL PHONE Not Used

6-65
Underhood Fuse BlockThe underhood fuse/relay block is located near the
battery in the engine compartment. See ªEngine
Compartment Overviewº in the Index for more
information on its location. Lift the cover for access
to the fuse/relay block.
You will see fuses to the top right of the fuse/relay block
once you remove the cover. These are spare fuses and
can be used accordingly.
You can remove fuses with a fuse extractor. The fuse
extractor is located in the fuse/relay 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.

6-67
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)Name Usage
STARTER Starter (Relay)
PARK LP Parking Lamps
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 Climate Control System
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

6-68
Name Usage
B/U LP Backup Lamps, Automatic
Transmission Shift Lock
Control System
ATC Automatic Transfer Case
RR DEFOG Rear Window Defogger, Heated
Mirrors (Relay)
RTD Autoride
(Real Time Damping)
RR PRK Right Rear Parking Lamps
ECM B VCM/PCM
F/PMP Fuel Pump (Relay)
O2 A Oxygen Sensors
O2 B Oxygen Sensors
LR PRK Left Rear Parking Lamps
RR DEFOG Rear Window Defogger, Heated
Mirrors
HDLP Headlamps (Relay)
TRL PRK Parking Lamps Trailer Wiring
PRIME Not UsedName Usage
RT HDLP Right Headlamps
DRL Daytime Running Lamps (Relay)
HTD MIR Heated Mirrors
LT HDLP Left Headlamps
A/C Air Conditioning
AUX PWR Cigarette Lighter, Auxiliary
Power Outlets
SEO 2 Special Equipment Option Power,
Power Seats
SEO 1 Special Equipment Option Power
DRL Daytime Running Lamps
A/C A/C (Relay)
FOG LP Fog Lamps
FOG LP Fog Lamps (Relay)
RADIO Audio System, Instrument Cluster,
Climate Control System
CIGAR Cigarette Lighter, Auxiliary
Power Outlets

6-69
Name Usage
RT TURN Right Turn Signals
BTSI Automatic Transmission Shift
Lock Control System
LT TURN Left Turn Signals
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
Bulb Number
Low
-Beam Headlamps 9005 or 9005LL. . . . . . . . . .
(Long Life) (Preferred)
High
-Beam Headlamps 9005. . . . . . . . . . . . . . . . . . .
Daytime Running Lamps (DRL) 3157KX or. . . . . . .
4157K (Preferred)
Front Marker Lamp 194. . . . . . . . . . . . . . . . . . . . . .
Front Parking and Turn Lamp 3157 or. . . . . . . . . . .
3157K (long life)
Rear Marker Lamp, Taillamp and
Stop Lamp 3157. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Turn Lamp 3157. . . . . . . . . . . . . . . . . . . . . . . . .
Back
-up Lamp 3157. . . . . . . . . . . . . . . . . . . . . . . . . .
For replacement bulbs not listed here, please consult
your dealer.

7-18
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.
Automatic Transmission Check
Check the transmission fluid level; add if needed.
See ªAutomatic Transmission Fluidº in the Index.
A fluid loss may indicate a problem. Check the system
and repair if needed.At Least Once a Year
Key Lock Cylinders Service
Lubricate the key lock cylinders with the lubricant
specified in Part D.
Body Lubrication Service
Lubricate all hood latch assembly, secondary latch, pivots,
spring anchor, release pawl, door hinges, liftgate hinge,
liftgate linkage, liftgate handle pivot points, latch bolt, fuel
door hinge, locks and folding seat hardware. Part D tells
you what to use. More frequent lubrication may be
required when exposed to a corrosive environment.

7-19
Starter Switch Check
CAUTION:
When you are doing this check, the vehicle could
move suddenly. If it does, you or others could be
injured. Follow the steps below.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake and the regular
brake. See ªParking Brakeº in the Index if necessary.
Do not use the accelerator pedal, and be ready to turn
off the engine immediately if it starts.
3. Try to start the engine in each gear. The starter
should work only in PARK (P) or NEUTRAL (N).
If the starter works in any other position, your
vehicle needs service.Automatic Transmission Shift Lock
Control System Check
CAUTION:
When you are doing this check, the vehicle could
move suddenly. If it does, you or others could be
injured. Follow the steps below.
1. Before you start, be sure you have enough room
around the vehicle. It should be parked on a
level surface.
2. Firmly apply the parking brake. See ªParking Brakeº
in the Index if necessary.
Be ready to apply the regular brake immediately if
the vehicle begins to move.
3. With the engine off, turn the key to the RUN
position, but don't start the engine. Without applying
the regular brake, try to move the shift lever out of
PARK (P) with normal effort. If the shift lever
moves out of PARK (P), your vehicle needs service.

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.