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6.6L V8 Engine
1. Battery - North America 0199.
2. Radiator Pressure Cap. See Cooling
System 0191.
3. Coolant Recovery Tank. See Cooling
System 0191. 4. Engine Oil Dipstick. See
“Checking Engine
Oil” under Engine Oil 0184.
5. Engine Cooling Fan (Out of View). See Cooling System 0191.
6. Engine Air Cleaner/Filter 0189. 7. Engine Oil Fill Cap. See
“When to Add
Engine Oil” underEngine Oil 0184.
8. Power Steering Fluid Reservoir. See Power Steering Fluid 0196.
9. Engine Compartment Fuse Block 0206.
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To replace one of these bulbs:1. Remove the screws (3) that secure the license plate bulb assembly (2).
2. Turn the bulb socket (1) counterclockwise and pull the bulb straight out of the
socket.
3. Install the new bulb.
4. Reverse Steps 1 and 2 to reinstall the license plate bulb assembly.
Electrical System
Electrical System Overload
The vehicle has fuses and circuit breakers to
protect against an electrical system
overload.
When the current electrical load is too
heavy, the circuit breaker opens and closes,
protecting the circuit until the current load
returns to normal or the problem is fixed.
This greatly reduces the chance of circuit
overload and fire caused by electrical
problems. Fuses and circuit breakers protect power
devices in the vehicle.
Replace a bad fuse with a new one of the
identical size and rating.
If there is a problem on the road and a fuse
needs to be replaced, the same amperage
fuse can be borrowed. Choose some feature
of the vehicle that is not needed to use and
replace it as soon as possible.
Headlamp Wiring
An electrical overload may cause the lamps
to go on and off, or in some cases to
remain off. Have the headlamp wiring
checked right away if the lamps go on and
off or remain off.
Windshield Wipers
If the wiper motor overheats due to heavy
snow or ice, the windshield wipers will stop
until the motor cools and will then restart.
Although the circuit is protected from
electrical overload, overload due to heavy
snow or ice may cause wiper linkage
damage. Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an electrical
problem and not snow or ice, be sure to get
it fixed.
Fuses and Circuit Breakers
The wiring circuits in the vehicle are
protected from short circuits by a
combination of fuses and circuit breakers.
This greatly reduces the chance of damage
caused by electrical problems.
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{Danger
Fuses and circuit breakers are marked
with their ampere rating. Do not exceed
the specified amperage rating when
replacing fuses and circuit breakers. Use
of an oversized fuse or circuit breaker can
result in a vehicle fire. You and others
could be seriously injured or killed.
{Warning
Installation or use of fuses that do not
meet GM’s original fuse specifications is
dangerous. The fuses could fail, and result
in a fire. You or others could be injured
or killed, and the vehicle could be
damaged.See
Accessories and Modifications 0178 and
General Information 0178.
To check a fuse, look at the silver-colored
band inside the fuse. If the band is broken
or melted, replace the fuse. Be sure to
replace a bad fuse with a new one of the
identical size and rating.
Fuses of the same amperage can be
temporarily borrowed from another fuse
location, if a fuse goes out. Replace the fuse
as soon as possible.
Engine Compartment Fuse Block
The fuse block is in the engine compartment
on the driver side of the vehicle.
Vehicles with Upfitter Content
See www.gmupfitter.com for upfitter
provisions and best practices.
Caution
Spilling liquid on any electrical
component on the vehicle may damage
it. Always keep the covers on any
electrical component.
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The vehicle may not be equipped with all of
the fuses, relays, and features shown.Fuses Usage
1 ABS motor
2 ABS module
3 Right trailer stoplamp/ Turn signal lamp
4 –
5 –
6 Fuel system control module/Ignition
7 Body control module 5
8 Body control module 7
9 Body control module 4
10 Instrument cluster 11 Trailer wiring
12 –
13 Interior rear vision camera module
14 Windshield washer
16 Horn 17 Transmission
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FusesUsage
18 A/C
19 Engine control module battery
20 Left stop/turn cutaway lamp
21 Left stop/turn trailer lamp
22 Right stop/turn cutaway lamp
23 NOX Sensor (Diesel only)
24 Fuel pump 25 Auxiliary power outlet
26 Body control module 3 27 Special equipment option
28 Airbag
29 Steering wheel sensor
30 Engine control module ignition
31 Transmission control module Ignition Fuses
Usage
32 Transmission control module 1 battery
33 Rear parking aid module
34 NOX Sensor (Diesel only)
35 Fuel heater control module (Diesel only)
36 Fuel system control module battery
41 Transmission control module 2, battery
signal
42 Trailer wiring
43 Electro viscous fan clutch (Diesel only)
44 Starter solenoid 45 Engine control module, powertrain signal 2
46 DC-AC inverter 47 –
51 Left high-beam headlamp Fuses
Usage
52 Right high-beam headlamp
53 Left low-beam headlamp
54 Right low-beam headlamp
55 Wipers
56 Canister vent solenoid
58 Body control module 2
59 Body control module 1 61 Engine oil solenoid/ Crankcase vent heater
(Diesel only)
62 O2 sensor 2
63 –
64 Mass airflow/ Canister vent
65 Ignition coils/injectors - odd
66 Daytime running lamps 2
67 Daytime running lamps 1
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FusesUsage
68 Auxiliary stoplamps
69 External power for trailer
70 Upfitter stoplamps 71 Fuel heater/FlexFuel sensor
72 Body control module 6
73 Lighter/Data link connector
74 Front blower 75 Engine control module
76 Soot sensors (Diesel only)
77 O2 sensor 1
78 Engine control module/ Powertrain signal 1
79 Ignition coils/injectors - even Relays
Usage
15 Run/Crank
37 NOX Sensor (Diesel only)
38 Fuel pump
39 Crank
40 A/C compressor 48 Electro viscous fan clutch (Diesel only)
49 Powertrain 50 –
57 –
60 – Auxiliary Fuse Block
This component is near the fuse block in the
engine compartment
Fuses Usage
MR-1 Upfitter 1
MR-2 Upfitter 2
MR-3 Upfitter power control
Relays Usage
MR Rel 1 Upfitter 1
MR Rel 2 Upfitter 2
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Mega Fuse Holder
FuseUsage
1 Starter motor
Floor Console Fuse Block
The floor console fuse block is under the driver seat.
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The vehicle may not be equipped with all of
the fuses, relays, and features shown.Mini-Fuses Usage
F1 –
F2 Steering wheel sensor
F3 Auxiliary parking lamps
F4 Front parking lamps F5 Trailer parking lamps
F6 Upfitter/Parking lamps F7 Right rear parking lamp
F8 Left rear parking lamp
F9 Exterior rear mirror switch/ Door
lock-unlock control
upfitter/Front camera
module
F10 Airbag/Automatic occupant sensing
F11 –/OnStar
F12 –
F13 HVAC 2
F14 HVAC 1 F15 Reflected LED display Mini-Fuses Usage
F16 Upfitter aux 1/Gas ambulance
F17 Heated outside mirrors
F18 Rear window defogger
F19 Compass
F20 Radio/Chime/SiriusXM satellite radio
F21 Remote function actuator/Tire pressure
monitor
F22 Ignition switch/Discrete logic ignition sensor
F23 Instrument cluster
F24 –
F25 HVAC control
F26 Auxiliary/Trailer reverse lamps
F27 Reverse tail lamps
F28 Upfitter 2/Reading lamps/Ambulance
F29 Rear blower
F30 Upfitter/Courtesy lamps Mini-Fuses Usage
F31 Front door lock
F32 Rear door lock
F33 Cargo door unlock
F34 Front passenger door unlock
F35 Rear passenger door unlock
F36 Driver door unlock F37 –
F38 –
Relays Usage K1 Run
K2 –
K3 Parking lamps
K4 Upfitter 2 K5 Rear window defogger
K6 Retained accessory power