trailer GMC YUKON DENALI 2008 Owner's Guide

Engine Fan Noise
Your vehicle has electric cooling fans. You might hear
the fans spinning at low speed during most everyday
driving. The fans can turn off if no cooling is required.
Under heavy vehicle loading, trailer towing, and/or
high outside temperatures, or if you are operating the
air conditioning system, the fans can change to high
speed and you might hear an increase in fan noise.
This is normal and indicates that the cooling system is
functioning properly. The fans change to low speed
when additional cooling is no longer required.
Power Steering Fluid
SeeEngine Compartment
Overview on page 5-12for
reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power steering uid
unless you suspect there is a leak in the system or
you hear an unusual noise. A uid loss in this system
could indicate a problem. Have the system inspected
and repaired.
How to Check Power Steering Fluid
To check the power steering uid, do the following:
1. Turn the key off and let the engine compartment
cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a
clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the uid level
on the dipstick.
The level should be at the FULL COLD mark.
If necessary, add only enough uid to bring the
level up to the mark.
5-34

Underhood Fuse Block
The underhood fuse block is located in the engine
compartment, on the driver side of the vehicle. Lift the
cover for access to the fuse/relay block.
Notice:Spilling liquid on any electrical components
on your vehicle may damage it. Always keep the
covers on any electrical component.
To remove fuses, hold the end of the fuse between your
thumb and index nger and pull straight out.
Fuses Usage
1 Right Trailer Stop/Turn Lamp
2Electronic Stability Suspension
Control, Automatic Level Control
Exhaust
3 Left Trailer Stop/Turn Lamp
4 Engine Controls
5Engine Control Module, Throttle
Control
5-111

Fuses Usage
6 Trailer Brake Controller
7 Front Washer
8 Oxygen Sensors
9 Antilock Brakes System 2
10 Trailer Back-up Lamps
11 Driver Side Low-Beam Headlamp
12 Engine Control Module (Battery)
13Fuel Injectors, Ignition Coils
(Right Side)
14Transmission Control Module
(Battery)
15 Vehicle Back-up Lamps
16Passenger Side Low-Beam
Headlamp
17 Air Conditioning Compressor
18 Oxygen Sensors
19 Transmission Controls (Ignition)
20 Fuel Pump
21 Fuel System Control Module
22 Headlamp Washers
23 Rear Windshield Washer
24Fuel Injectors, Ignition Coils
(Left Side)
25 Trailer Park LampsFuses Usage
26 Driver Side Park Lamps
27 Passenger Side Park Lamps
28 Fog Lamps
29 Horn
30Passenger Side High-Beam
Headlamp
31 Daytime Running Lamps
32 Driver Side High-Beam Headlamps
33 Daytime Running Lamps 2
34 Sunroof
35Key Ignition System, Theft Deterrent
System
36 Windshield Wiper
37 SEO B2 Uptter Usage (Battery)
38 Electric Adjustable Pedals
39 Climate Controls (Battery)
40 Airbag System (Ignition)
41 Amplier
42 Audio System
43Miscellaneous (Ignition), Cruise
Control
44 Liftgate Release
45 Airbag System (Battery)
46 Instrument Panel Cluster
5-112

Fuses Usage
47 Power Take-Off
48Auxiliary Climate Control (Ignition),
Compass-Temperature Mirror
49Center High-Mounted Stoplamp
(CHMSL)
50 Rear Defogger
51 Heated Mirrors
52 SEO B1 Uptter Usage (Battery)
53Cigarette Lighter, Auxiliary Power
Outlet
54Automatic Level Control Compressor
Relay, SEO Uptter Usage
55 Climate Controls (Ignition)
56Engine Control Module, Secondary
Fuel Pump (Ignition)
J-Case Fuses Usage
60 Cooling Fan 1
61 Automatic Level Control Compressor
62 Heavy Duty Antilock Brake System
63 Cooling Fan 2
64 Antilock Brake System 1
65 Starter
66 Stud 2 (Trailer Brakes)
67 Left Bussed Electrical Center 1
J-Case Fuses Usage
68 Electric Running Boards
69 Heated Windshield Washer System
70 Not Used
71Stud 1 (Trailer Connector
Battery Power)
72 Mid-Bussed Electrical Center 1
73 Climate Control Blower
74 Power Liftgate Module
75 Left Bussed Electrical Center 2
Relays Usage
FAN HI Cooling Fan High Speed
FAN LO Cooling Fan Low Speed
ENG EXH VLV Not Used
FAN CNTRL Cooling Fan Control
HDLP LO/HID Low-Beam Headlamps
FOG LAMP Front Fog Lamps
A/C CMPRSR Air Conditioning Compressor
STRTR Starter
PWR/TRN Powertrain
FUEL PMP Fuel Pump
PRK LAMP Parking Lamps
REAR DEFOG Rear Defogger
RUN/CRANK Switched Power
5-113

(c)Visually inspect hoses and have them replaced if
they are cracked, swollen, or deteriorated. Inspect all
pipes, fittings, and clamps; replace with genuine parts as
needed. To help ensure proper operation, a pressure test
of the cooling system and pressure cap and cleaning the
outside of the radiator and air conditioning condenser is
recommended at least once a year.
(d)Inspect wiper blades for wear, cracking, or
contamination. Clean the windshield and wiper blades, if
contaminated. Replace wiper blades that are worn or
damaged. See Windshield Wiper Blade Replacement on
page 5-53 and Windshield, Backglass, and Wiper
Blades on page 5-103for more information.
(e)Make sure the safety belt reminder light and safety
belt assemblies 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 see Checking the Restraint
Systems on page 1-92.
(f)Lubricate all key lock cylinders, 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. More frequent lubrication may be
required when exposed to a corrosive environment.
Applying silicone grease on weatherstrips with a clean
cloth will make them last longer, seal better, and not stick
or squeak.(g)Inspect system. Check all fuel and vapor lines and
hoses for proper hook-up, routing, and condition.
Check that the purge valve works properly, if equipped.
Replace as needed.
(h)Change automatic transmission fluid and filter if the
vehicle is mainly driven under one or more of these
conditions:
In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police, or delivery
service.
(i)Drain, flush, and refill cooling system. This service
can be complex; you should have your dealer/retailer
perform this service. See Engine Coolant on page 5-23
for what to use. Inspect hoses. Clean radiator,
condenser, pressure cap, and filler neck. Pressure test
the cooling system and pressure cap.
(j)A fluid loss in any vehicle system could indicate a
problem. Have the system inspected and repaired and
the fluid level checked. Add fluid if needed.
(k)If you drive regularly under dusty conditions, inspect
the filter at each engine oil change.
(l)Visually inspect belt for fraying, excessive cracks, or
obvious damage. Replace belt if necessary.
(m)Check vent hose at transfer case for kinks and
proper installation.
6-8

Tires (cont.)
Ination - Tire Pressure................................5-60
Inspection and Rotation................................5-67
Installing the Spare Tire................................5-85
Pressure Monitor Operation...........................5-64
Pressure Monitor System..............................5-62
Removing the Flat Tire.................................5-85
Removing the Spare Tire and Tools...............5-79
Secondary Latch System..............................5-90
Spare Tire..................................................5-98
Storing a Flat or Spare Tire and Tools............5-94
Tire Sidewall Labeling..................................5-56
Tire Terminology and Denitions....................5-58
Uniform Tire Quality Grading.........................5-72
Wheel Alignment and Tire Balance.................5-74
Wheel Replacement.....................................5-74
When It Is Time for New Tires......................5-69
Tow/Haul Mode...............................................2-34
Tow/Haul Mode Light.......................................3-47
Towing
Recreational Vehicle.....................................4-40
Towing a Trailer..........................................4-42
Your Vehicle...............................................4-40
Traction
Locking Differential........................................ 4-5
StabiliTrak
®System....................................... 4-6Trailer
Recommendations.......................................4-55
Transmission
Fluid, Automatic...........................................5-20
Transmission Operation, Automatic....................2-30
Trip Odometer................................................3-33
Turn and Lane-Change Signals.......................... 3-8
Turn Signal/Multifunction Lever........................... 3-8
U
Ultrasonic Rear Parking Assist (URPA)...............2-44
Uniform Tire Quality Grading............................5-72
Universal Home Remote System.......................2-50
Operation...................................................2-51
Using this Manual............................................... iii
V
Vehicle
Control........................................................ 4-3
Damage Warnings........................................... iv
Loading......................................................4-34
Symbols......................................................... iv
Vehicle Customization, DIC..............................3-64
13