Page 294 of 366
Instrument Panel Fuse Block
There are two instrument panel fuse blocks located behind the instrument panel on the passenger’s side of
the vehicle.
Be sure to replace fuses with fuses of the same rating. Do not use fuses of higher amperage than those indicated on
the fuse block.
Fuse Block 1
5-88
Page 295 of 366
Fuse Usage
RH PARK LP Right-hand Parking Lamps
LH PARK LP Left-hand Parking Lamps
RADIO U Radio
PWR WINDOW Power Windows
BRAKE ISO Brake Warning Lamp
SPARE Spare Fuse
L-RR TRUCK Left Rear Trailer Wiring
SPARE Spare Fuse
SPARE Spare Fuse
SPARE Spare Fuse
R-RR TRUCK Right Rear Trailer Wiring
SPARE Spare Fuse
Relay Usage
BRAKE LAMPC4/C5 Brake Lamps,
C6/C7/C8 Tractor/Trailer Wiring
IGN 4 IgnitionRelay Usage
MARKER LP Sidemarker and Clearance Lamps
HTD FUEL LB7/LG4 Heated Fuel
AIR HTR LG4 Air Heater
ECU MAINTAIN LG4 Electronic Control Unit
DRL Daytime Running Lamps
CHMSL ISO Center High Mounted Stop Lamp
HTD MIRR Heated Mirrors
R-TRN TLR Right Trailer Turn Signal
L-TRN TLR Left Trailer Turn Signal
SPARE Spare Relay
SPARE Spare Relay
SPARE Spare Relay
5-89
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Circuit Breaker Usage
1 Stoplamps
2 Center High Mounted Stop Lamps
3 Parking Lamps
4 Powertrain Control Module
5 Auxiliary Wiring
6 Heater/Air Conditioning
7 Hazard Warning FlashersCircuit Breaker Usage
8 Power Post
9 Courtesy Lamps
10Warning Lights, Gages and
Indicators
11 Crank
12 Rear Axle
13Trailer Turn Signals/Hazard Warning
Flashers
14 Radio/Chime
15 Daytime Running Lamps
16 Air Bag System
17 Exterior/Interior Lamps
18 Parking Brake
19 Accessory Power
20 Ignition
21 Sidemarker Lamps
22 Turn Signal/Backup Lamps
23 Transmission
24 Chassis
A Spare
B Spare Fuse Block 2
5-90
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Underhood Fuse Block
When a circuit goes out, the problem could be in either
the primary or secondary underhood fuse blocks.
These blocks uses blade-type fuses.
Both underhood fuse
blocks are located in the
engine compartment,
on the passenger’s side of
the vehicle.
To access the fuse blocks, gently squeeze both sides of
the cover to unlatch the tabs at the top. Then, unsnap
both attachments at the bottom and remove the cover.
Be sure to replace fuses with fuses of the same
rating. Do not use fuses of higher amperage than those
indicated on the fuse block.Relay Usage
NOTE 1 LG4 Powertrain Control Valve,
L18/LB7 Fuel Pump, LG5 Heated
Fuel
IGN B Ignition
STARTER Starter
HORN Horn
IGN A Ignition Primary Underhood
Fuse Block
Primary Underhood Fuse Block
5-91
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Relay Usage
PTO Power Take-Off
REVERSE Reverse
NEUTRAL
STARTNeutral Start
Fuse Usage
RR DEFOG Rear Defog
ENG 1 Engine 1
ENG 3 Engine 3
PCM-B Powertrain Control Module
BLANK Empty
ENG 4 Engine 4
ENG 2 Engine 2
HTD FUEL Heated Fuel
BLANK EmptyFuse Usage
BLANK Empty
BLANK Empty
A/C COMP Air Conditioning Compressor
ABS 1 Anti-Lock Brake System 1
ABS 2 Anti-Lock Brake System 2
ABS 3 Anti-Lock Brake System 3
ENGINE Engine
E/A PUMP Electronic/Automatic Pump
HORN Horn
NOTE 2L18/LB7 Fuel, LG4 Powertrain
Control Valve, LG5 Electronic
Control Module
BLANK Empty
STUD A Spare
STUD B Spare
5-92
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Fuse Usage
IGN 1 Ignition 1
IGN 4 Ignition 4
IGN 3 Ignition 3
BATT/HAZ Battery/Hazard Warning Flashers
HEADLAMP Headlamps
LIGHTING Interior/Exterior Lamps
HVAC Comfort Control System
NOTE C4/C5 Electric Brake,
C6/C7/C8 Brake Lamps
Capacities and Speci cations
Capacities and Speci cations
Engine RPO
7.2L L6 HEUI Fuel System LG5
8.1L V8 SPFI Fuel System L18
7.8L L6 Common Rail Fuel System LG4
6.6L V8 Common Rail Fuel System LB7/LLY Secondary Underhood
Fuse Block
5-93
Page 355 of 366

Driving on Snow or Ice....................................4-26
Driving Through Deep Standing Water...............4-20
Driving Through Flowing Water.........................4-20
Dual Tire Operation.........................................5-69
E
Eaton®Fuller®Five and Six-Speed
Transmissions and TTC Spicer Seven-Speed
Transmissions.............................................2-30
Eaton
®Fuller®Nine and Ten-Speed
Non-Synchronized Manual Transmissions........2-32
Electric Air Compressor...................................5-51
Electrical Connections......................................4-36
Electrical System
Add-On Equipment......................................5-86
Fuses and Circuit Breakers...........................5-87
Fusible Links..............................................5-87
Headlamp Wiring.........................................5-86
Power Windows and Other Power Options......5-87
Windshield Wiper Fuses...............................5-87
Elevated Idle/Exhaust Restrictor........................2-21
Engine
Air Cleaner/Filter.........................................5-30
Battery.......................................................5-55
Change Engine Oil Light...............................3-39
Check and Service Engine Soon Light............3-37Engine (cont.)
Checks Before Operating..............................2-22
Coolant..............................................5-32, 5-35
Coolant Heater............................................2-23
Coolant Temperature Gage...........................3-35
Diesel Engine Exhaust Brake........................2-25
Drive Belt Routing......................................5-103
Exhaust.....................................................2-37
Fan Noise..................................................5-43
Oil .....................................................5-20, 5-25
Overheating................................................5-36
Overspeed Warning Light..............................3-39
Reduced Power Light...................................3-41
Shutdown Warning Light...............................3-39
Starting Your Diesel.....................................2-14
Starting Your DURAMAX™ Diesel..................2-19
Starting Your Gasoline..................................2-12
Engine Alarm and Automatic Shutdown..............2-16
Engine Coolant Level Check.............................6-24
Engine Cooling System Service........................6-26
Engine Cover Check.......................................6-28
Engine Oil Additives................................5-23, 5-29
Engine Oil Level Check...................................6-24
Engine Road Speed Governor..........................3-25
Engine Speed Limiting.....................................3-25
Engine Starter Over-Crank Protection.................2-12
Event Data Records (EDR)................................ 7-5
Exhaust Brake Indicator Light...........................3-40
5
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Exhaust Restrictor (Diesel Engines)...................2-18
Exhaust System Check....................................6-27
Express-Down Feature.....................................2-10
Extender, Safety Belt.......................................1-26
Exterior Lamps...............................................3-13
F
Filter
Engine Air Cleaner......................................5-30
Filter Minder Gage..........................................3-44
Finding a Station............................3-46, 3-49, 3-53
Finish Care....................................................5-80
Finish Damage...............................................5-83
Fixed Mast Antenna........................................3-59
Flat Tire........................................................5-75
Flat Tire, Changing.........................................5-76
Fluid
Automatic Transmission................................5-31
Manual Transmission....................................5-32
Power Steering...........................................5-43
Windshield Washer......................................5-44
Fluid Leaks Check..........................................6-28
FM ...............................................................3-57
Folding the Rear Seat (Crew Cab).................... 1-7
Footnotes......................................................6-19
Fore-and-Aft Adjustment.................................... 1-4Four-Wheel and Six-Wheel Drum Brakes
(Air Only)...................................................5-49
Four-Wheel Disc Brakes
(Hydraulic Only)..........................................5-49
Front Wheel Bearings with Oil-Filled Hubs..........5-67
Fuel............................................................... 5-6
Additives...................................................... 5-7
Diesel Engine Fuel........................................ 5-8
Filling a Portable Fuel Container....................5-18
Filling Your Tank..........................................5-17
Filter..........................................................5-64
Filter Replacement.......................................5-15
Fuels in Foreign Countries............................5-16
Gage.........................................................3-42
Gasoline Octane........................................... 5-6
Gasoline Specifications.................................. 5-6
Primary Filter and Water Separator................5-65
Running Out of Fuel....................................5-15
Secondary Filter and Water Separator/Heater....5-66
Very Cold Weather Operation........................5-10
Water in Fuel..............................................5-10
Water in Warning Light.................................3-43
What Fuel to Use.......................................... 5-8
Fuel Filter (Diesel Engines)..............................5-65
Fuel Filter (Gasoline Engines)...........................5-64
Fuel Priming..................................................5-13
Fuses
Fuses and Circuit Breakers...........................5-87
Windshield Wiper.........................................5-87
6