GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
Driving and Operating 239
pickups. Trailer pin box extensions
and sliding fifth-wheel hitch
assemblies can help this condition.
There should be at least 15 cm (6 in)
of clearance between the top of the
pickup box and the bottom of the
trailer shelf that extends over
the box.
Safety Chains
Always attach chains between the
vehicle and the trailer. Cross the
safety chains under the tongue of
the trailer to help prevent the tongue
from contacting the road if it
becomes separated from the hitch.
Instructions about safety chains
may be provided by the hitch
manufacturer or by the trailer
manufacturer. If the trailer being
towed weighs up to 2 271 kg
(5,000 lb) with a factory-installed
step bumper, safety chains may be
attached to the attaching points on
the bumper; otherwise, safety
chains should be attached to holes
on the trailer hitch platform. Always
leave just enough slack so the
combination can turn. Never allow
safety chains to drag on the ground.
Trailer Brakes
A loaded trailer that weighs more
than 900 kg (2,000 lb) needs to have
its own brake system that is
adequate for the weight of the
trailer. Be sure to read and follow
the instructions for the trailer brakes
so they are installed, adjusted, and
maintained properly.
Do not tap into the vehicle's
hydraulic brake system.
Auxiliary Battery
The auxiliary battery provision can
be used to supply electrical power
to additional equipment that may be
added, such as a slide-in camper.
If equipped, this relay will be on the
driver side of the vehicle, next to the
underhood electrical center.
Be sure to follow the proper
installation instructions included with
any electrical equipment that is
installed.
Caution
Leaving electrical equipment on
for extended periods will drain the
battery. Always turn off electrical
equipment when not in use and
do not use equipment that
exceeds the maximum amperage
rating of 30 amps for the auxiliary
battery provision.
Trailer Wiring Harness
The vehicle is equipped with one of
the following wiring harnesses for
towing a trailer or hauling a slide-in
camper.
Basic Trailer Wiring
All regular, double cab, and crew
cab pickups have a seven-wire
trailer towing harness.
For vehicles not equipped with
heavy-duty trailering, the harness is
secured to the vehicle's frame
behind the spare tire mount. The
harness requires the installation of a
trailer connector, which is available
through your dealer.
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
Vehicle Care 285
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
The wiring circuits in the vehicle are
protected from short circuits by
fuses. This greatly reduces the
chance of fires caused by electrical
problems.
Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you 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
you can.
Engine Compartment
Fuse Block
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
The engine compartment fuse block
is in the engine compartment, on
the driver side of the vehicle.
Lift the cover to access the fuse
block.
Caution
Spilling liquid on any electrical
component on the vehicle may
damage it. Always keep the
covers on any electrical
component.
A fuse puller is available in the left
instrument panel fuse block.
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
288 Vehicle Care
Micro Fuses(2 Pin) Usage
54 Aeroshutter
55 Front Washer
Micro Fuses (3 Pin) Usage
56 Air Conditioning Compressor/
Battery Regulated
Voltage Control
57 Air Conditioning Compressor
Module/
Battery Pack
58 Transmission Control Module/
Engine Control
Module
59 Headlamps
Micro
Relays Usage
60 Fuel Pump
61 Upfitter 2 Micro
Relays Usage
62 Upfitter 3
63 Upfitter 4
64 Trailer Parking Lamps
65 Run/Crank
66 Upfitter 1
67 Fuel Pump 2
68 Air Conditioning Control
69 Starter
Mini Relays Usage 70 Rear Window Defogger
71 Engine Control Module
Solid State Relay Usage
72 Cooling Fan ClutchInstrument Panel Fuse
Block (Right)
The right instrument panel fuse
block access door is on the
passenger side edge of the
instrument panel.
Pull off the cover to access the fuse
block.
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
Vehicle Care 289
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Number Usage
1 Accessory Power Outlet 3 Number Usage
2 Accessory Power Outlet 4
7 Body Control Module 4
8 Body Control Module 8
9 Rear Seat Entertainment
10 Cargo Lamp
15 Steering Wheel Controls
18 Radio
19 Spare
20 Sunroof
23 Airbag/Info
26 Export/Power Take Off/SEO Battery 1
27 Obstacle Detection/ USB Ports
28 Body Control Module 2
32 SEO Battery 2
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
Vehicle Care 291
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Number Usage
1 Accessory Power Outlet 2 Number Usage
2 SEO Retained Accessory Power
3 Universal Garage Door Opener/Inside
Rearview Mirror
6 Body Control Module 3
7 Body Control Module 5
8 Driver Window Switch/Mirror Switch
9 Spare
10 Accessory Power Outlet Retained
Accessory Power
11 Accessory Power Outlet Battery
12 Accessory Power Outlet 1/Cigarette
Lighter
13 Discrete Logic Ignition Switch
14 Switch Backlighting
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
378 OnStar
.Obtain the Wi-Fi®hotspot name
or SSID and password,
if equipped.
Press
Qto connect to an
Advisor to:
. Verify account information or
update contact information.
. Get driving directions.
. Receive a Diagnostic check of
the vehicle's key operating
systems.
. Receive Roadside Assistance.
. Manage Wi-Fi Settings,
if equipped.
Press
>to get a priority connection
to an OnStar Advisor available
24/7 to:
. Get help for an emergency.
. Be a Good Samaritan or
respond to an AMBER Alert.
. Get assistance in severe
weather or other crisis situations
and find evacuation routes.
OnStar Services
Emergency
Emergency Services require an
active, OnStar subscription plan
(excludes Basic Plan). With
Automatic Crash Response, built-in
sensors can automatically alert a
specially trained OnStar Advisor
who is immediately connected in to
the vehicle to help.
Press
>for a priority connection to
an OnStar Advisor who can contact
emergency service providers, direct
them to your exact location, and
relay important information.
With OnStar Crisis Assist, specially
trained Advisors are available
24 hours a day, 7 days a week, to
provide a central point of contact,
assistance, and information during a
crisis.
With Roadside Assistance, Advisors
can locate a nearby service provider
to help with a flat tire, a battery
jump, or an empty gas tank.
Security
If equipped, OnStar provides these
services:
. With Stolen Vehicle Assistance,
OnStar Advisors can use GPS to
pinpoint the vehicle and help
authorities quickly recover it.
. With Remote Ignition Block,
if equipped, OnStar can block
the engine from being restarted.
. With Stolen Vehicle Slowdown,
if equipped, OnStar can work
with law enforcement to
gradually slow the vehicle down.
Navigation
OnStar navigation requires a
specific OnStar subscription plan.
Press
Qto receive Turn-by-Turn
directions or have them sent to the
vehicle’s navigation screen,
if equipped.
Turn-by-Turn Navigation
1. PressQto connect to an
Advisor.
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