2021 CHEVROLET BLAZER wiring

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
Seats and Restraints 59
{Warning
For up to 10 seconds after the vehicle is
turned off and the battery is
disconnected, an airbag can still inflate
during improper service. You can be
injured if you are close to an airbag
when it inflates. Avoid yellow connectors.
They are probably part of the airbag
system. Be sure to follow proper service
procedures, and make sure the person
performing work for you is qualified to
do so.
Adding Equipment to the
Airbag-Equipped Vehicle
Adding accessories that change the vehicle's
frame, bumper system, height, front end,
or side sheet metal may keep the airbag
system from working properly.
The operation of the airbag system can also
be affected by changing, including
improperly repairing or replacing, any parts
of the following:
.Airbag system, including airbag modules,
front or side impact sensors, sensing and
diagnostic module, or airbag wiring
.Front seats, including stitching, seams or
zippers
.Seat belts
.Steering wheel, instrument panel,
overhead console, ceiling trim, or pillar
garnish trim
.Inner door seals, including speakers
Your dealer and the service manual have
information about the location of the airbag
modules and sensors, sensing and diagnostic
module, and airbag wiring along with the
proper replacement procedures.
In addition, the vehicle has a passenger
sensing system for the front outboard
passenger position, which includes sensors
that are part of the passenger seat. The
passenger sensing system may not operate
properly if the original seat trim is replaced
with non-GM covers, upholstery, or trim; or
with GM covers, upholstery, or trim
designed for a different vehicle. Any object,
such as an aftermarket seat heater or a
comfort-enhancing pad or device, installed
under or on top of the seat fabric, could
also interfere with the operation of the
passenger sensing system. This could either
prevent proper deployment of the passenger
airbag(s) or prevent the passenger sensing system from properly turning off the
passenger airbag(s). See
Passenger Sensing
System 055.
If the vehicle has rollover roof-rail airbags,
see Different Size Tires and Wheels 0303 for
additional important information.
If the vehicle must be modified because you
have a disability and have questions about
whether the modifications will affect the
vehicle's airbag system, or if you have
questions about whether the airbag system
will be affected if the vehicle is modified for
any other reason, call Customer Assistance.
See Customer Assistance Offices 0351.
Airbag System Check
The airbag system does not need regularly
scheduled maintenance or replacement.
Make sure the airbag readiness light is
working. See Airbag Readiness Light 098.
Caution
If an airbag covering is damaged, opened,
or broken, the airbag may not work
properly. Do not open or break the airbag
coverings. If there are any opened or
broken airbag coverings, have the airbag
(Continued)

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
Instruments and Controls 87
An indicator light on the outlet turns on to
show it is in use. The light comes on when
the ignition is on, equipment requiring less
than 150 watts is plugged into the outlet,
and no system fault is detected.
The indicator light does not come on when
the ignition is off or if the equipment is not
fully seated into the outlet.
If equipment is connected using more than
150 watts or a system fault is detected, a
protection circuit shuts off the power supply
and the indicator light turns off. To reset
the circuit, unplug the item and plug it back
in or turn the Retained Accessory Power
(RAP) off and then back on. SeeRetained
Accessory Power (RAP) 0205. The power
restarts when equipment using 150 watts or
less is plugged into the outlet and a system
fault is not detected.
The power outlet is not designed for the
following and may not work properly if they
are plugged in:
.Equipment with high initial peak wattage,
such as compressor-driven refrigerators
and electric power tools
.Other equipment requiring an extremely
stable power supply, such as
microcomputer-controlled electric blankets
and touch sensor lamps
.Medical equipment
See High Voltage Devices and Wiring 0279.
Wireless Charging
If equipped, the vehicle has wireless
charging in the storage bin in front of the
floor console. The system operates at
145 kHz and wirelessly charges one Qi
compatible smartphone. The power output
of the system is capable of charging at a
rate up to 3 amp (15W), as requested by the
compatible smartphone. See Radio
Frequency Statement 0357.
{Warning
Wireless charging can affect the
operation of an implanted pacemaker or
other medical devices. If you have one, it
is recommended to consult with your
doctor before using the wireless charging
system.
The vehicle must be on, in ACC/ACCESSORY,
or Retained Accessory Power (RAP) must be
active. The wireless charging feature may
not correctly indicate charging when the
vehicle is in RAP. See Retained Accessory
Power (RAP) 0205. The operating temperature is
−20 °C (−4 °F)
to 60 °C (140 °F) for the charging system
and 0 °C (32 °F) to 35 °C (95 °F) for the
smartphone.
{Warning
Remove all objects from the charging pad
before charging your compatible
smartphone. Objects, such as coins, keys,
rings, paper clips, or cards, between the
smartphone and charging pad will
become very hot. On the rare occasion
that the charging system does not detect
an object, and the object gets wedged
between the smartphone and charger,
remove the smartphone and allow the
object to cool before removing it from
the charging pad, to prevent burns.

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
98 Instruments and Controls
since the charging system is not able to
provide full power at engine idle. As engine
speeds are increased, this condition should
correct itself as higher engine speeds allow
the charging system to create maximum
power.
The vehicle can only be driven for a short
time with the readings outside the normal
operating range. If the vehicle must be
driven, turn off all accessories, such as the
radio and air conditioner, and unplug all
chargers and accessories.
Readings outside the normal operating
range indicate a possible problem in the
electrical system. Have the vehicle serviced
as soon as possible.
Seat Belt Reminders
Driver Seat Belt Reminder Light
There is a driver seat belt reminder light on
the instrument cluster.
When the vehicle is started, this light
flashes and a chime may come on to remind
the driver to fasten their seat belt.
Then the light stays on solid until the belt is
buckled. This cycle may continue several
times if the driver remains or becomes
unbuckled while the vehicle is moving.
If the driver seat belt is buckled, neither the
light nor the chime comes on.
Front Passenger Seat Belt Reminder
Light
The vehicle may have a front passenger seat
belt reminder light near the passenger
airbag status indicator. SeePassenger
Sensing System 055.
When the vehicle is started, this light
flashes and a chime may come on to remind
passengers to fasten their seat belt. Then the light stays on solid until the belt is
buckled. This cycle continues several times if
the front passenger remains or becomes
unbuckled while the vehicle is moving.
If the front passenger seat belt is buckled,
neither the chime nor the light comes on.
The front passenger seat belt reminder light
and chime may come on if an object is put
on the seat such as a briefcase, handbag,
grocery bag, laptop, or other electronic
device. To turn off the reminder light and/or
chime, remove the object from the seat or
buckle the seat belt.
Airbag Readiness Light
This light shows if there is an electrical
problem with the airbag system. The system
check includes the airbag sensor(s), the
passenger sensing system, the pretensioners,
the airbag modules, the wiring, and the
crash sensing and diagnostic module. For
more information on the airbag system, see
Airbag System
050.

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
250 Driving and Operating
attempt to tap into your vehicle's hydraulic
brake system. If you do, both the vehicle
antilock brakes and the trailer brakes may
not function, which could result in a crash.
Trailer Wiring Harness
Basic Trailer Wiring
The trailer wiring harness, with a seven-pin
connector, is at the rear of the vehicle and
is tied to the vehicle's frame. The harness
requires the installation of a trailer
connector, which is available through your
dealer.
Use only a round, seven-wire connector with
flat blade terminals meeting SAE J2863
specifications for proper electrical
connectivity.
The seven-wire harness contains the
following trailer circuits:
.Yellow: Left Stop/Turn Signal
.Green: Right Stop/Turn Signal
.Brown: Tail/Parking Lamps
.White: Trailer Ground
.Red: Stop Lamp Supply Voltage
.Black: Back Up Lamp Supply Voltage
.Blue: Service BrakesThe fuse for the electric trailer brake circuit
is in the engine compartment fuse block,
but the wires may not be connected. They
should be connected by your dealer or a
qualified service center. To control electric
trailer brakes, a trailer brake controller needs
to be installed on the vehicle by your dealer
or a qualified service center. See electric
brake control wiring provisions.
If a battery outside the vehicle is being
charged, place the vehicle in Tow/Haul
Mode. This will boost the vehicle system
voltage and properly charge the battery.
If the trailer is too light for Tow/Haul Mode,
turn on the non-HID only headlamps as a
second way to boost the vehicle system
voltage and charge the battery.
Electric Trailer Brake Control Wiring
Provisions
Wiring provisions for an aftermarket electric
trailer brake controller are included with the
vehicle as part of the trailer wiring package.
The harness contains the following circuits:
These wiring provisions for an electric trailer
brake controller are included with the
vehicle as part of the trailer wiring package.
The body harness, inside the front driver
side instrument panel, contains blunt cut wires below the headlamp switch for the
electric trailer brake controller. The harness
contains the following wires:
.Blue: Electric Trailer Brakes
.Blue: Battery Feed
.White/Blue: Brake Apply Signal
.Black: Ground
Refer to the aftermarket electric trailer 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.
Trailer Lamps
Always check all trailer lamps are working at
the beginning of each trip, and periodically
on longer trips.
Turn Signals When Towing a Trailer
When properly connected, the trailer turn
signals will illuminate to indicate the vehicle
is turning, changing lanes, or stopping.
When towing a trailer, the arrows on the
instrument cluster will illuminate even if the
trailer is not properly connected or the bulbs
are burned out.

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
Vehicle Care 253
Vehicle Care
General Information
General Information . . . . . . . . . . . . . . . . . . . 254
California Proposition 65 Warning . . . . . 254
California Perchlorate MaterialsRequirements . . . . . . . . . . . . . . . . . . . . . . . . 254
Accessories and Modifications . . . . . . . . . 254
Vehicle Checks
Doing Your Own Service Work . . . . . . . . . 255
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Engine Compartment Overview . . . . . . . . 257
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
Engine Oil Life System . . . . . . . . . . . . . . . . 264
Automatic Transmission Fluid . . . . . . . . . 265
Engine Air Filter Life System . . . . . . . . . . 265
Engine Air Cleaner/Filter . . . . . . . . . . . . . . 265
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 267
Engine Overheating . . . . . . . . . . . . . . . . . . . . 271
Washer Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Battery - North America . . . . . . . . . . . . . . . 274
All-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . 275
Automatic Transmission Shift Lock Control Function Check . . . . . . . . . . . . . . 275
Park Brake and P (Park) Mechanism Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
Wiper Blade Replacement . . . . . . . . . . . . . 276 Windshield Replacement . . . . . . . . . . . . . . . 277
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . . . . . . . 278
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . 278
High Intensity Discharge (HID)
Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
LED Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Back-Up Lamps . . . . . . . . . . . . . . . . . . . . . . . . 278
Electrical System
High Voltage Devices and Wiring . . . . . . 279
Electrical System Overload . . . . . . . . . . . . 279
Fuses and Circuit Breakers . . . . . . . . . . . . 280
Engine Compartment Fuse Block . . . . . . 280
Instrument Panel Fuse Block . . . . . . . . . . 284
Rear Compartment Fuse Block . . . . . . . . . 285
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
All-Season Tires . . . . . . . . . . . . . . . . . . . . . . . 288
Winter Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
Summer Tires . . . . . . . . . . . . . . . . . . . . . . . . . 289
Tire Sidewall Labeling . . . . . . . . . . . . . . . . . 289
Tire Designations . . . . . . . . . . . . . . . . . . . . . . 291
Tire Terminology and Definitions . . . . . . 292
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . 294
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 Tire Pressure Monitor System . . . . . . . . . 296
Tire Pressure Monitor Operation . . . . . . 297
Tire Inspection . . . . . . . . . . . . . . . . . . . . . . . . 300
Tire Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . 300
When It Is Time for New Tires . . . . . . . . 301
Buying New Tires . . . . . . . . . . . . . . . . . . . . . 302
Different Size Tires and Wheels . . . . . . . 303
Uniform Tire Quality Grading . . . . . . . . . 303
Wheel Alignment and Tire Balance . . . . 305
Wheel Replacement . . . . . . . . . . . . . . . . . . . 305
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . 306
Tire Sealant and Compressor Kit . . . . . . . 307
Storing the Tire Sealant and
Compressor Kit . . . . . . . . . . . . . . . . . . . . . . . 313
Tire Changing . . . . . . . . . . . . . . . . . . . . . . . . . . 313
Compact Spare Tire . . . . . . . . . . . . . . . . . . . . 317
Jump Starting
Jump Starting - North America . . . . . . . . 318
Towing the Vehicle
Towing the Vehicle . . . . . . . . . . . . . . . . . . . . 320
Recreational Vehicle Towing . . . . . . . . . . . 321
Appearance Care
Exterior Care . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Interior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
Vehicle Care 279
2. Remove the access cover.
3. Turn the bulb socket counterclockwiseand pull the bulb straight out of the
socket. 4. Replace the bulb and reverse Steps 1–3 to
reinstall.
Electrical System
High Voltage Devices and Wiring
{Warning
Exposure to high voltage can cause shock,
burns, and even death. The high voltage
components in the vehicle can only be
serviced by technicians with special
training.
High voltage components are identified
by labels. Do not remove, open, take
apart, or modify these components. High
voltage cable or wiring has orange
covering or labels. Do not probe, tamper
with, cut, or modify high voltage cable or
wiring.
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.

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
280 Vehicle Care
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.
{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 0254 and
General Information 0254.
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 underhood fuse block is in the engine
compartment, on the driver side of the
vehicle.

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
372 Index
Fuses (cont'd)Instrument Panel Fuse Block . . . . . . . . . . . 284
Rear Compartment Fuse Block . . . . . . . . . 285
G
Garage Door Opener . . . . . . . . . . . . . . . . . . . . . . 117
Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
Gauges
Engine Coolant Temperature . . . . . . . . . . . . 96
Engine Oil Temperature . . . . . . . . . . . . . . . . . 96
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Speedometer . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Trip Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Voltmeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Warning Lights and Indicators . . . . . . . . . . 89
General Information Service and Maintenance . . . . . . . . . . . . . . 331
Towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
Global Positioning System (GPS) . . . . . . . . . . 152
Glove Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
GM Mobility Reimbursement Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352
Guidance Problems with the Route . . . . . . . . . . . . . . 153
H
Hazard Warning Flashers . . . . . . . . . . . . . . . . .124
HD Radio Technology . . . . . . . . . . . . . . . . . . . . . 135
Head Restraints . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
HeadlampsAiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . 278
Daytime Running Lamps (DRL) . . . . . . . . . 123
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
High Intensity Discharge (HID)Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
High-Beam On Light . . . . . . . . . . . . . . . . . . . 106
High/Low Beam Changer . . . . . . . . . . . . . . 122
Lamps On Reminder . . . . . . . . . . . . . . . . . . . 107
Heated Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Steering Wheel . . . . . . . . . . . . . . . . . . . . . . . . . 83
Heated and Ventilated Front Seats . . . . . . . 40
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Heater
Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .182
High Voltage Devices and Wiring . . . . . . . . 279
High-Beam On Light . . . . . . . . . . . . . . . . . . . . . 106
High-Speed Operation . . . . . . . . . . . . . . . . . . . 295
Hill and Mountain Roads . . . . . . . . . . . . . . . . 195
Hill Start Assist (HSA) . . . . . . . . . . . . . . . . . . . . . 212 Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Hooks
Shopping Bag . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
How to Wear Seat Belts Properly . . . . . . . . . 45
HVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .182
I
If the System Needs Service . . . . . . . . . . . . . . 153
Ignition Positions . . . . . . . . . . . . . . . . . . . . . . . . 200
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Indicator Pedestrian Ahead . . . . . . . . . . . . . . . . . . . . . . 104
Vehicle Ahead . . . . . . . . . . . . . . . . . . . . . . . . . 103
Infants and Young Children, Restraints . . . . .61
Information Publication Ordering . . . . . . . . . . . . . . . . . . . 356
Infotainment System . . . . . . . . . . . . . . . . . . . . 359
Instrument Cluster . . . . . . . . . . . . . . . . . . . . 90, 93
Instrument Panel Overview . . . . . . . . . . . . . . . . 4
Interior Rearview Mirrors . . . . . . . . . . . . . . . . . 26
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 128
J
Jump Starting - North America . . . . . . . . . . . .318
K
Keyless Entry Remote (RKE) System . . . . . . . . . . . . . . . . . . . . 7