2018 CHEVROLET SILVERADO 1500 Z71 light

Chevrolet Silverado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
11349200) - 2018 - CRC - 2/27/18
Driving and Operating 319
Vehicle SeriesTrailer WeightWeight-Distributing Hitch
Usage Hitch Distribution
1500 Up to 3 175 kg (7,000 lb) OptionalRefer to trailer
manufacturer ’s
recommendation
1500 Over 3 175 kg (7,000 lb) Required50%
2500/3500 Up to 9 080 kg (20,000 lb) OptionalRefer to trailer
manufacturer ’s
recommendation
1. Front of Vehicle
2. Body to Ground Distance
When using a weight-distributing
hitch, measure distance (2) before
coupling the trailer to the hitch ball.
Measure the height again after the
trailer is coupled and adjust the
spring bars so the distance (2) is as
close as possible to halfway
between the two measurements.
Fifth-Wheel and Gooseneck
Trailering
Fifth-wheel and gooseneck trailers
can be used with many pickup
models. These trailers place a
larger percentage of the weight
(kingpin weight) on the tow vehicle than conventional trailers. Make
sure this weight does not cause the
vehicle to exceed GAWR or GVWR.
Fifth-wheel or gooseneck kingpin
weight should be 15 to 25% of the
trailer weight up to the maximum
amount specified in the trailering
chart for the vehicle. See
“Weight of
the Trailer” underTrailer Towing
0 300.
The hitch should be located in the
pickup bed so that its centerline is
over or slightly in front of the rear
axle. Take care that it is not so far
forward that it will contact the back
of the cab in sharp turns. This is

Chevrolet Silverado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
11349200) - 2018 - CRC - 2/27/18
322 Driving and Operating
For vehicles with the fifth wheel/
gooseneck trailer package, the
harness connector is mounted on
the inside of the pickup bed behind
the rear wheel.
The seven-wire harness contains
the following trailer circuits:
.Green/Violet: Right Stop/Turn
Signal
. Yellow/Gray: Left Stop/Turn
Signal
. Gray/Brown: Taillamps/Parking
Lamps
. White/Green: Back-up Lamps
. Red/Green: Battery Feed .
White: Ground
. Blue: Electric Trailer Brake
To help charge a remote
(non-vehicle) battery, press the Tow/
Haul Mode button at the end of the
shift lever. If the trailer is too light for
Tow/Haul Mode, turn on the
headlamps to help charge the
battery.
Camper/Fifth-Wheel Trailer Wiring
Package
For vehicles without the fifth wheel/
gooseneck trailer package,
seven-wire camper harness is under
the rear bumper, attached to the
frame near the rear crossmember.
A connector must be added to the
wiring harness that connects to the
camper.
The harness contains the following
camper/trailer circuits:
. Green/Violet: Right Stop/Turn
Signal
. Yellow/Gray: Left Stop/Turn
Signal .
Gray/Brown: Taillamps/Parking
Lamps
. White/Green: Back-up Lamps
. Red/Green: Battery Feed
. White: Ground
. Blue: Electric Trailer Brake
If the vehicle is equipped with the
heavy-duty trailering option, see
“Heavy-Duty Trailer Wiring Harness
Package” earlier in this section.Electric Brake Control Wiring
Provisions
Wiring provisions for an electric
trailer brake controller are included
with the vehicle as part of the trailer
wiring package. The instrument
panel contains blunt cut wires above
the parking brake assembly for the
electric trailer brake controller.
The harness contains the following
circuits:
.
Blue: Electric Trailer Brakes
. Red/Black or Red/Blue:
Battery Feed
. White/Blue: Brake Apply Signal

Chevrolet Silverado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
11349200) - 2018 - CRC - 2/27/18
Driving and Operating 323
.Black: Ground
Be sure to consult the aftermarket
electric brake controller owner ’s
manual to determine wire color
coding of the electric trailer brake
controller. The wire colors on the
brake controller may be different
from the vehicle.
The electric trailer brake controller
should be installed by your dealer or
a qualified service center.
Tow/Haul Mode
Pressing this button at the end of
the shift lever turns on and off the
Tow/Haul Mode.
This indicator light on the instrument
cluster comes on when the Tow/
Haul Mode is on.
Tow/Haul is a feature that assists
when pulling a heavy trailer or a
large or heavy load. See Tow/Haul
Mode 0262.
Tow/Haul is designed to be most
effective when the vehicle and
trailer combined weight is at least
75% of the vehicle's Gross
Combined Weight Rating (GCWR).
See “Weight of the Trailer” under
Trailer Towing 0300. Tow/Haul is
most useful under the following
driving conditions:
. When pulling a heavy trailer or a
large or heavy load through
rolling terrain.
. When pulling a heavy trailer or a
large or heavy load in
stop-and-go traffic. .
When pulling a heavy trailer or a
large or heavy load in busy
parking lots where improved low
speed control of the vehicle is
desired.
Operating the vehicle in Tow/Haul
when lightly loaded or with no trailer
at all will not cause damage.
However, there is no benefit to the
selection of Tow/Haul when the
vehicle is unloaded. Such a
selection when unloaded may result
in unpleasant engine and
transmission driving characteristics
and reduced fuel economy. Tow/
Haul is recommended only when
pulling a heavy trailer or a large or
heavy load.
Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for use with electric trailer brakes or
most electric over hydraulic trailer
brakes.

Chevrolet Silverado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
11349200) - 2018 - CRC - 2/27/18
Driving and Operating 327
If the disconnect occurs while
the vehicle is moving, this
message will continue until the
ignition is turned off. This
message will also turn off if it is
acknowledged or if the trailer
harness is reconnected.
. There is an electrical fault in the
wiring to the trailer brakes. This
message will continue as long
as there is an electrical fault in
the trailer wiring. This message
will also turn off if it is
acknowledged.
To determine if the electrical fault is
on the vehicle side or trailer side of
the trailer wiring harness
connection: 1. Disconnect the trailer wiring harness from the vehicle.
2. Turn the ignition off.
3. Wait 10 seconds, then turn the ignition back to RUN.
4. If the CHECK TRAILER WIRING message reappears,
the electrical fault is on the
vehicle side. If the CHECK TRAILER
WIRING message only
reappears when connecting the
trailer wiring harness to the
vehicle, the electrical fault is on
the trailer side.
SERVICE TRAILER BRAKE
SYSTEM: This message will display
when there is a problem with the
ITBC system. If this message
continues over multiple ignition
cycles, there is a problem with the
ITBC system. Have the vehicle
serviced.
If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message displays
while driving, the ITBC system may
not be fully functional or may not
function at all. When traffic
conditions allow, carefully pull the
vehicle over to the side of the road
and turn the ignition off. Check the
wiring connection to the trailer and
turn the ignition back on. If either of
these messages continues, either
the vehicle or trailer needs service. A GM dealer may be able to
diagnose and repair problems with
the trailer. However, any diagnosis
and repair of the trailer is not
covered under the vehicle warranty.
Contact your trailer dealer for
assistance with trailer repairs and
trailer warranty information.
Trailer Sway
Control (TSC)
Vehicles with StabiliTrak have a
Trailer Sway Control (TSC) feature.
Trailer sway is unintended
side-to-side motion of a trailer while
being towed. If the vehicle is towing
a trailer and the TSC detects that
sway is increasing, the vehicle
brakes are selectively applied at
each wheel, to help reduce
excessive trailer sway. If the vehicle
is equipped with the Integrated
Trailer Brake Control (ITBC) system,
and the trailer has the electric
actuated brake system, StabiliTrak
may also apply the trailer brakes.
If TSC is enabled, the Traction
Control System (TCS)/StabiliTrak
warning light will flash on the

Chevrolet Silverado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
11349200) - 2018 - CRC - 2/27/18
Driving and Operating 329
Warning (Continued)
(20-25 mph) and fully apply
the manual trailer brake
apply lever. Also check that
the trailer brake lamps and
other lamps are functioning
correctly.
. If the trailer brakes are not
operating properly at any
time, or if a DIC message
indicates problems with the
trailer connections or trailer
brakes, carefully pull the
vehicle over to the side of
the road when traffic
conditions allow.
Conversions and
Add-Ons
Add-On Electrical
Equipment
{Warning
The Data Link Connector (DLC) is
used for vehicle service
and Emission Inspection/
Maintenance testing. See
Malfunction Indicator Lamp
(Check Engine Light) 0147.
A device connected to the DLC —
such as an aftermarket fleet or
driver-behavior tracking device —
may interfere with vehicle
systems. This could affect vehicle
operation and cause a crash.
Such devices may also access
information stored in the vehicle’s
systems.
Caution
Some electrical equipment can
damage the vehicle or cause
components to not work and
would not be covered by the
vehicle warranty. Always check
with your dealer before adding
electrical equipment.
Add-on equipment can drain the
vehicle's 12-volt battery, even if the
vehicle is not operating.
The vehicle has an airbag system.
Before attempting to add anything
electrical to the vehicle, see
Servicing the Airbag-Equipped
Vehicle 090 and Adding Equipment
to the Airbag-Equipped Vehicle
0 90.
For information on wiring auxiliary
switches, see www.gmupfitter.com
or contact your dealer.

Chevrolet Silverado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
11349200) - 2018 - CRC - 2/27/18
334 Vehicle Care
Vehicle Care
General Information
General Information . . . . . . . . . . 335
California Proposition65 Warning . . . . . . . . . . . . . . . . . 336
California Perchlorate Materials Requirements . . . . . 336
Accessories and Modifications . . . . . . . . . . . . . . . . 336
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 337
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 337
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 338
Engine Oil . . . . . . . . . . . . . . . . . . . . 343
Engine Oil Life System . . . . . . . 346
Automatic Transmission Fluid (6-Speed Transmission) . . . . . 347
Automatic Transmission Fluid (8-Speed Transmission) . . . . . 350
Manual Transmission Fluid . . . 350
Hydraulic Clutch . . . . . . . . . . . . . . 351
Engine Air Cleaner/Filter . . . . . . 351
Cooling System . . . . . . . . . . . . . . 352
Engine Overheating . . . . . . . . . . 356 Overheated Engine Protection
Operating Mode . . . . . . . . . . . . . 358
Engine Fan . . . . . . . . . . . . . . . . . . . 358
Power Steering Fluid (1500 Series) . . . . . . . . . . . . . . . . . . . . . . 359
Power Steering Fluid (2500/ 3500 Series) . . . . . . . . . . . . . . . . 359
Washer Fluid . . . . . . . . . . . . . . . . . 359
Brakes . . . . . . . . . . . . . . . . . . . . . . . 360
Brake Fluid . . . . . . . . . . . . . . . . . . . 361
Battery - North America . . . . . . 362
Four-Wheel Drive . . . . . . . . . . . . . 363
Front Axle . . . . . . . . . . . . . . . . . . . . 364
Rear Axle . . . . . . . . . . . . . . . . . . . . 365
Noise Control System . . . . . . . . 366
Starter Switch Check . . . . . . . . . 367
Automatic Transmission Shift Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 368
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 368
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 368
Wiper Blade Replacement . . . . 369
Windshield Replacement . . . . . 369
Gas Strut(s) . . . . . . . . . . . . . . . . . . 370
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 371
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 371
Halogen Bulbs . . . . . . . . . . . . . . . . 371
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . 371
LED Lighting . . . . . . . . . . . . . . . . . 371
Headlamps, Front Turn Signal,
Sidemarker, and Parking
Lamps . . . . . . . . . . . . . . . . . . . . . . 372
Fog Lamps . . . . . . . . . . . . . . . . . . . 373
Taillamps (Chassis Cab Models) . . . . . . . . . . . . . . . . . . . . . 373
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 373
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 375
Electrical System
High Voltage Devices andWiring . . . . . . . . . . . . . . . . . . . . . . . 375
Electrical System Overload . . . 375
Fuses and Circuit Breakers . . . 376
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 376
Instrument Panel Fuse Block (Right) . . . . . . . . . . . . . . . . . . . . . . 380
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . . . 381

Chevrolet Silverado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
11349200) - 2018 - CRC - 2/27/18
Vehicle Care 351
reason for fluid loss. If a leak
occurs, take the vehicle to your
dealer service department and have
it repaired as soon as possible. See
Recommended Fluids and
Lubricants0451 for the proper fluid
to use.
Hydraulic Clutch
For vehicles with a manual
transmission, it is not necessary to
regularly check clutch fluid unless
you suspect there is a leak in the
system. Adding fluid will not correct
a leak. A fluid loss in this system
could indicate a problem. Have the
system inspected and repaired.
When to Check and What
to Use
The hydraulic clutch fluid reservoir
cap has this symbol on it. See
Engine Compartment Overview
0 338 for reservoir location.
Refer to Recommended Fluids and
Lubricants 0451 for the proper fluid
to use. The fluid requires changing.
See Maintenance Schedule 0443.
How to Check and Add Fluid
Visually check the clutch fluid
reservoir. The hydraulic clutch fluid
system should be closed and
sealed.
Do not remove the cap to check the
fluid level or to top-off the fluid level.
Remove the cap only when
necessary to add the proper fluid.
Engine Air Cleaner/Filter
If the vehicle has a diesel engine,
see “8-Cylinder Pickup Models”
under “Engine Air Cleaner/Filter” in
the Duramax diesel supplement for
the correct inspection and
replacement procedures. The engine air cleaner/filter is on
the passenger side of the engine
compartment. See
Engine
Compartment Overview 0338.
When to Inspect the Engine Air
Cleaner/Filter
For intervals on changing and
inspecting the engine air filter, see
Maintenance Schedule 0443.
How to Inspect the Engine Air
Cleaner/Filter
Do not start the engine or have the
engine running with the engine air
cleaner/filter housing open. Before
removing the engine air cleaner/
filter, make sure that the engine air
cleaner/filter housing and nearby
components are free of dirt and
debris. Remove the engine air
cleaner/filter. Lightly tap and shake
the engine air cleaner/filter (away
from the vehicle), to release loose
dust and dirt. Inspect the engine air
cleaner/filter for damage, and
replace if damaged. Do not clean
the engine air cleaner/filter or
components with water or
compressed air.

Chevrolet Silverado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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Vehicle Care 355
the full cold mark. If it is not, there
may be a leak in the cooling
system.
If coolant is visible but the coolant
level is not at or above the full cold
mark, see“How to Add Coolant to
the Coolant Surge Tank for Gasoline
Engines,” following.
How to Add Coolant to the
Coolant Surge Tank for
Gasoline Engines
If the vehicle has a diesel engine,
see“Cooling System” in the
Duramax diesel supplement for the
proper coolant fill procedure.
{Warning
Spilling coolant on hot engine
parts can burn you. Coolant
contains ethylene glycol and it will
burn if the engine parts are hot
enough.
{Warning
Plain water, or other liquids such
as alcohol, can boil before the
proper coolant mixture will. With
plain water or the wrong mixture,
the engine could get too hot but
there would not be an overheat
warning. The engine could catch
fire and you or others could be
burned.
{Warning
Steam and scalding liquids from a
hot cooling system are under
pressure. Turning the pressure
cap, even a little, can cause them
to come out at high speed and
you could be burned. Never turn
the cap when the cooling system,
including the pressure cap, is hot.
Wait for the cooling system and
pressure cap to cool.
Caution
Failure to follow the specific
coolant fill procedure could cause
the engine to overheat and could
cause system damage. If coolant
is not visible in the surge tank,
contact your dealer.
If no coolant is visible in the surge
tank, add coolant.
Light-Duty
Coolant Surge
Tank
Pressure CapHeavy-Duty
Coolant Surge
Tank
Pressure Cap
1. Remove the coolant surge tank pressure cap when the cooling
system, including the coolant
surge tank pressure cap and
upper radiator hose, is no
longer hot.