Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions the clutch is not engaged. This improves fuel
economy and reduces fan noise. Under heavy vehicle
loading, trailer towing, and/or high outside temperatures,
the fan speed increases when the clutch engages so
you may hear an increase in fan noise. This is normal
and should not be mistaken as the transmission slipping
or making extra shifts. It is merely the cooling system
functioning properly. The fan will slow down when
additional cooling is not required and the clutch
disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
Power Steering Fluid
SeeEngine Compartment
Overview on page 5-12
for 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.
5-34
Fuses Usage
5 Driver’s Side High-Beam Headlamp
6 Driver’s Side Low-Beam Headlamp
7 Rear Window Washer
8 Automatic Transfer Case
9 Windshield Washer
10 Powertrain Control Module B
11 Fog Lamps
12 Stoplamp
13 Cigarette Lighter
14 Not Used
15 Electric Adjustable Pedal
16 Truck Body Controller, Ignition 1
17 Crank
18 Airbag
19 Trailer Electric Brake
20 Cooling Fan
21 Horn
22 Ignition E
23 Electronic Throttle ControlFuses Usage
24Instrument Panel Cluster, Driver
Information Center
25 Automatic Shift Lock Control System
26 Engine 1
27 Back-Up
28 Powertrain Control Module 1
29 Oxygen Sensor
30 Air Conditioning
31 Truck Body Controller
32 Trailer
33 Anti-lock Brakes (ABS)
34 Ignition A
35 Blower Motor
36 Ignition B
50 Passenger’s Side Trailer Turn
51 Driver’s Side Trailer Turn
52 Hazard Flashers
53 Headlamp Driver Module
54 Air Injection Reactor (AIR) Solenoid
56 Air Injection Reactor (AIR) Pump
5-98
Fuses Usage
6 Driver’s Side Low-Beam Headlamp
7 Rear Window Washer
8 Automatic Transfer Case
9 Windshield Washer
10 Powertrain Control Module B
11 Fog Lamps
12 Stoplamp
13 Cigarette Lighter
14 Ignition Coils
15 Canister Vent
16 Truck Body Controller, Ignition 1
17 Crank
18 Airbag
19 Trailer Electric Brake
20 Cooling Fan
21 Horn
22 Ignition E
23 Electronic Throttle Control
24Instrument Panel Cluster, Driver
Information Center
25 Automatic Shift Lock Control System
26 Engine 1Fuses Usage
27 Back-Up
28 Powertrain Control Module 1
29 Powertrain
30 Air Conditioning
31 Injector Bank A
32 Trailer
33 Anti-lock Brakes (ABS)
34 Ignition A
35 Blower Motor
36 Ignition B
50 Passenger’s Side Trailer Turn
51 Driver’s Side Trailer Turn
52 Hazard Flashers
53 Transmission
54 Oxygen Sensor Bank B
55 Oxygen Sensor Bank A
56 Injector Bank B
57 Headlamp Driver Module
58 Truck Body Controller 1
59 Electric Adjustable Pedal
61Vehicle Stability Enhancement
System (StabiliTrak
®)
5-101
Fuses Usage
24 Unlock
25 Blank
26 Blank
27OnStar
®Overhead Battery,
OnStar®System
28 Sunroof
29 Rainsense™ Wipers
30 Parking Lamps
31 Truck Body Controller Accessory
32 Truck Body Controller 5
33 Front Wipers
34 Vehicle Stop
35 Transmission Control Module
36 Heat Ventilation Air Conditioning B
37 Front Parking Lamps
38 Left Turn Signal
Fuses Usage
39 Heat Ventilation Air Conditioning I
40 Truck Body Controller 4
41 Radio
42 Trailer Park
43 Right Turn Signal
44 Heat Ventilation Air Conditioning
45 Rear Fog Lamps
46 Auxiliary Power 1
47 Ignition 0
48 Four-Wheel Drive
49 Blank
50 Truck Body Controller Ignition
51 Brakes
52 Truck Body Controller Run
5-104
(e)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 airbag
coverings, and have them repaired or replaced.
The airbag system does not need regular maintenance.
(f)Lubricate all key lock cylinders, hood latch assembly,
secondary latch, pivots, spring anchor, release pawl,
rear compartment hinges, outer liftgate handle pivot
points, rear door detent link, roller mechanism, liftgate
handle pivot points, latch bolt, fuel door hinge, cargo 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 hoses for cracks, cha ng, leaks, kinks,
and proper installation.(h)Change automatic transmission uid and lter 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, ush, and re ll cooling system. This service
can be complex; you should have your dealer perform
this service. See Engine Coolant on page 5-24 for
what to use. Inspect hoses. Clean radiator, condenser,
pressure cap, and ller neck. Pressure test the
cooling system and pressure cap.
(j)A uid loss in any vehicle system could indicate a
problem. Have the system inspected and repaired and
the uid level checked. Add uid if needed.
(k)If you drive regularly under dusty conditions, inspect
the lter at each engine oil change.
(l)Visually inspect belt for fraying, excessive cracks, or
obvious damage. Replace belt if necessary.
6-8