2023 GMC SIERRA heater

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 311
Caution
If the air cleaner/filter is off, dirt can
easily get into the engine, which could
damage it. Always have the air
cleaner/filter in place when driving.
Cooling System
If the vehicle has the Duramax diesel
engine, see the Duramax diesel supplement.
The cooling system allows the engine to
maintain the correct working temperature.
{Warning
An underhood electric fan can start up
even when the engine is not running and
can cause injury. Keep hands, clothing,
and tools away from any underhood
electric fan.
1. Engine Cooling Fan (Out of View)
2. Coolant Surge Tank and Pressure Cap
{Warning
Do not touch heater, radiator, a/c pipes
or hoses, or other engine parts. They can
be very hot and can burn you. Do not
run the engine if there is a leak; all
coolant could leak out. That could cause
an engine fire and can burn you. Fix any
leak before driving the vehicle.
Engine Coolant
The cooling system in the vehicle is filled
with DEX-COOL engine coolant. This coolant
is designed to remain in the vehicle for
5 years or 240 000 km (150,000 mi),
whichever occurs first.
The following explains the cooling system
and how to check and add coolant when it
is low. If there is a problem with engine
overheating, seeEngine Overheating 0313.
What to Use
{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.
Use a 50/50 mixture of clean, drinkable
water and DEX-COOL coolant. This mixture:
.Gives freezing protection down to −37 °C
(−34 °F), outside temperature.
.Gives boiling protection up to 129 °C
(265 °F), engine temperature.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
314 Vehicle Care
In addition, there are ENGINE OVERHEATED
STOP ENGINE, ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS REDUCED
messages in the Driver Information
Center (DIC).
If the decision is made not to lift the hood
when this warning appears, get service help
right away. SeeRoadside Assistance Program
0 399.
If the decision is made to lift the hood,
make sure the vehicle is parked on a level
surface.
Check to see if the engine cooling fans are
running. If the engine is overheating, the
fans should be running. If they are not, do
not continue to run the engine and have the
vehicle serviced.
If the engine or transmission detects an
impending hot fluid condition, then the
transmission may force upshifts to limit
temperatures. Downshifts may also be
prevented in this instance. Normal operation
may continue unless the display indicates
there is a hot condition and engine should
be idled.If Steam is Coming from the Engine
Compartment
{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.
If No Steam is Coming from the Engine
Compartment
The ENGINE OVERHEATED STOP ENGINE or
the ENGINE OVERHEATED IDLE ENGINE
message, along with a low coolant
condition, can indicate a serious problem.
If there is an engine overheat warning, but
no steam is seen or heard, the problem may
not be too serious. Sometimes the engine
can get a little too hot when the vehicle:
.Climbs a long hill on a hot day.
.Stops after high-speed driving.
.Idles for long periods in traffic.
.Tows a trailer; see Trailer Towing0272.
If the ENGINE OVERHEATED STOP ENGINE or
the ENGINE OVERHEATED IDLE ENGINE
message appears with no sign of steam, try
this for a minute or so: 1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest fan
speed. Open the windows as necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or N (Neutral) and
let the engine idle.
If the temperature overheat gauge is no
longer in the overheat zone or an overheat
warning no longer displays, the vehicle can
be driven. Continue to drive the vehicle
slowly for about 10 minutes. Keep a safe
vehicle distance from the vehicle in front.
If the warning does not come back on,
continue to drive normally and have the
cooling system checked for proper fill and
function.
If the warning continues, pull over, stop, and
park the vehicle right away.
If there is still no sign of steam and the
vehicle is equipped with an engine driven
cooling fan, push down the accelerator until
the engine speed is about twice as fast as

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Index 419
DoorAjar Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . 24
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Power Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Drive Belt Routing, Engine . . . . . . . . . . . . . . . 395
Drive Systems Four-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . 321
Driver Assistance Systems . . . . . . . . . . . . . . . . . . . . 246
Information Center (DIC) . . . . . . . . . . . 128, 130
Mode Control . . . . . . . . . . . . . . . . . . . . . . . . . . 243
Mode Control Light . . . . . . . . . . . . . . . . . . . . 125
Teen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Driving Assistance Systems . . . . . . . . . . . . . . . . . . . . 257
Better Fuel Economy . . . . . . . . . . . . . . . . . . . 204
Characteristics and Towing Tips . . . . . . . . 268
Defensive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Distracted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Hill and Mountain Roads . . . . . . . . . . . . . . 212
If the Vehicle is Stuck . . . . . . . . . . . . . . . . . 214
Impaired . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Loss of Control . . . . . . . . . . . . . . . . . . . . . . . . 207
Off-Road . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . 207
Vehicle Load Limits . . . . . . . . . . . . . . . . . . . . 215
Wet Roads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 Driving (cont'd)
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
Dual Automatic Climate Control System . . . . 197
E
E85 or FlexFuel . . . . . . . . . . . . . . . . . . . . . . . . . . 264
ElectricParking Brake . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Parking Brake Light . . . . . . . . . . . . . . . . . . . . 122
Electrical Equipment, Add-On . . . . . . . . . . . . . . . . . . . . 297
System Overload . . . . . . . . . . . . . . . . . . . . . . 327
Electrical System Engine Compartment Fuse Block . . . . . . . 329
Fuses and Circuit Breakers . . . . . . . . . . . . . 329
Instrument Panel Fuse Block . . . . . . 333, 334
Electronic Stability Control (ESC) Off Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Emergency OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
Engine
Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . 310
Air Filter Life System . . . . . . . . . . . . . . . . . . 309
Check Light (Malfunction Indicator) . . . . 120
Compartment Overview . . . . . . . . . . . . . . . . 305
Coolant Temperature Gauge . . . . . . . . . . . . 117
Coolant Temperature Warning Light . . . 125 Engine (cont'd)
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . 311
Drive Belt Routing . . . . . . . . . . . . . . . . . . . . . 395
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 308
Oil Pressure Gauge . . . . . . . . . . . . . . . . . . . . . 116
Oil Pressure Light . . . . . . . . . . . . . . . . . . . . . . 126
Overheated Protection
Operating Mode . . . . . . . . . . . . . . . . . . . . . 315
Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
Power Messages . . . . . . . . . . . . . . . . . . . . . . . 135
Running While Parked . . . . . . . . . . . . . . . . . 230
Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Equipment, Towing . . . . . . . . . . . . . . . . . . . . . . 276
Event Data Recorders . . . . . . . . . . . . . . . . . . . . 406
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Extended Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . .37
Extended Parking . . . . . . . . . . . . . . . . . . . . . . . . 229
Extender, Seat Belt . . . . . . . . . . . . . . . . . . . . . . . 64
Exterior
Cargo Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
Lamp Controls . . . . . . . . . . . . . . . . . . . . . . . . . 139
Lamps Off Reminder . . . . . . . . . . . . . . . . . . . . 141
Lighting Battery Saver . . . . . . . . . . . . . . . . . 147

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Index 421
H
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Hazard Warning Flashers . . . . . . . . . . . . . . . . .142
HD Radio Technology . . . . . . . . . . . . . . . . . . . . 156
Head Restraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Head-Up Display (HUD) . . . . . . . . . . . . . . . . . . . 132
HeadlampsAiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . 325
Daytime Running Lamps (DRL) . . . . . . . . . . 141
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Headlamps, Front Turn Signal,Sidemarker, and Parking Lamps . . . . . . 325
High-Beam On Light . . . . . . . . . . . . . . . . . . . . 127
High/Low Beam Changer . . . . . . . . . . . . . . . 141
Lamps On Reminder . . . . . . . . . . . . . . . . . . . 128
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Steering Wheel . . . . . . . . . . . . . . . . . . . . . . . . 105
Ventilated Front Seats . . . . . . . . . . . . . . . . . . 56
Heater Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .196, 197
High-Beam On Light . . . . . . . . . . . . . . . . . . . . . . 127 Hill
Descent Control (HDC) . . . . . . . . . . . . . . . . . 242
Descent Control Light . . . . . . . . . . . . . . . . . . 123
Hill and Mountain Roads . . . . . . . . . . . . . . . . . 212
Hill Start Assist (HSA) . . . . . . . . . . . . . . . . . . . . 240
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
How to Wear Seat Belts Properly . . . . . . . . . 59
HVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .196, 197
I
If the System Needs Service . . . . . . . . . . . . . . 171
Ignition Positions . . . . . . . . . . . . . . . . . . . . 221, 223
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Indicator Vehicle Ahead . . . . . . . . . . . . . . . . . . . . . . . . . 124
Indicators
Warning Lights and Gauges . . . . . . . . . . . . . 111
Infants and Young Children, Restraints . . . . .77
Information Publication Ordering . . . . . . . . . . . . . . . . . . . 404
Infotainment Using the System . . . . . . . . . . . . . . . . . . . . . . 152
Infotainment System . . . . . . . . . . . . . . . . . . . . 407
Inspection Multi-Point Vehicle . . . . . . . . . . . . . . . . . . . . 387
Instrument Cluster . . . . . . . . . . . . . . . . . . . . . . . . 111
Instrument Panel Overview . . . . . . . . . . . . . . . . .5 Interior Rearview Mirrors . . . . . . . . . . . . . . . . . 40
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 2, 148
J
Jack
Auxiliary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Jump
Starting - North America . . . . . . . . . . . . . . . 367
K
Keyless EntryRemote (RKE) System Operation . . . . . 12, 14
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 11
L
Labeling, Tire Sidewall . . . . . . . . . . . . . . . . . . . 338
Lamps Auxiliary Roof Mounted Lamp . . . . . . . . . 144
Daytime Running (DRL) . . . . . . . . . . . . . . . . . 141
Dome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Exterior Cargo . . . . . . . . . . . . . . . . . . . . . . . . . 144
Exterior Controls . . . . . . . . . . . . . . . . . . . . . . . 139
Exterior Lamps Off Reminder . . . . . . . . . . . 141
Exterior Lighting Battery Saver . . . . . . . . 147
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Fog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
High/Low Beam Changer . . . . . . . . . . . . . . . 141
License Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . 327