2005 GMC SIERRA heater

If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. If your air conditioner is on, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and open the windows as necessary.
3. If you are in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving — DRIVE (D) or THIRD (3).
If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning does not come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there is still no sign of steam and your vehicle is
equipped with an engine-driven cooling fan, push down
the accelerator until the engine speed is about twice
as fast as normal idle speed for at least three minutes
while you are parked.
If there is still no sign of steam and your vehicle is
equipped with an electric engine cooling fan, idle the
engine for three minutes while you are parked.If you still have the warning,turn off the engine and get
everyone out of the vehicleuntil it cools down. Also,
see “Overheated Engine Protection Operating Mode”
later in this section.
You may decide not to lift the hood but to get service
help right away.
Overheated Engine Protection
Operating Mode (V8 Engines Only)
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates ring
groups of cylinders helps prevent engine damage. In
this mode, you will notice a loss in power and engine
performance. This operating mode allows your vehicle to
be driven to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant loss, change the oil and reset the oil
life system. SeeEngine Oil (Gasoline Engine) on
page 5-20.
5-39

If the coolant inside the coolant surge tank is boiling, do
not do anything else until it cools down. The vehicle
should be parked on a level surface.
The coolant level should
be at or above the FULL
COLD mark. If it is not, you
may have a leak at the
pressure cap or in
the radiator hoses, heater
hoses, radiator, water
pump or somewhere else
in the cooling system.
{CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Do not touch them.
If you do, you can be burned.
Do not run the engine if there is a leak. If you
run the engine, it could lose all coolant. That
could cause an engine re, and you could be
burned. Get any leak xed before you drive the
vehicle.
If there seems to be no leak and your vehicle is
equipped with an electric engine cooling fan, with the
engine on check to see if the cooling fan is running. If it
is not, your vehicle needs service. Turn off the engine.
If there seems to be no leak and your vehicle is
equipped with an engine-driven cooling fan, start the
engine again and see if the fan speed increases when
idle speed is doubled by pushing the accelerator
pedal down. If it does not, your vehicle needs service.
Turn off the engine.
5-41

Notice:Engine damage from running your engine
without coolant is not covered by your warranty.
SeeOverheated Engine Protection Operating Mode
(V8 Engines Only) on page 5-39for information
on driving to a safe place in an emergency.
Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your vehicle.
How to Add Coolant to the Coolant
Surge Tank for Gasoline Engines
If you have not found a problem yet, check to see if
coolant is visible in the surge tank. If coolant is visible
but the coolant level is not at or above the FULL COLD
mark, add a 50/50 mixture ofclean, drinkable water
and DEX-COOL
®coolant at the coolant surge tank, but
be sure the cooling system, including the coolant
surge tank pressure cap, is cool before you do it. See
Engine Coolant on page 5-35for more information.If no coolant is visible in the surge tank, add coolant
as follows:
{CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the coolant
surge tank pressure cap — even a little — they
can come out at high speed. Never turn the
cap when the cooling system, including the
coolant surge tank pressure cap, is hot. Wait
for the cooling system and coolant surge tank
pressure cap to cool if you ever have to turn
the pressure cap.
5-42

{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can boil
before the proper coolant mixture will. Your
vehicle’s coolant warning system is set for the
proper coolant mixture. With plain water or the
wrong mixture, your engine could get too hot
but you would not get the overheat warning.
Your engine could catch re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and a proper coolant.
Notice:In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
1. You can 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.
Turn the pressure cap slowly counterclockwise (left)
about one full turn. If you hear a hiss, wait for that
to stop. A hiss means there is still some pressure left.
2. Then keep turning the pressure cap slowly, and
remove it.
5-43

*1— Gasoline Engine and Diesel Engine.
*2— Gasoline Engine; ECMRPV — Diesel Engine.
*3— Gasoline Engine; FUEL HT — Diesel Engine.
*4— Gasoline Engine; ECM I — Diesel Engine.
*5— IGN/EDU
Fuses Usage
GLOW PLUGDiesel Glow Plugs and Intake
Air Heater
CUST FEED Gasoline Accessory Power
HYBRID Hybrid
STUD #1Auxiliary Power (Single
Battery and Diesels Only)/
Dual Battery (TP2) Do not
install fuse.
MBECMid Bussed Electrical Center
Power Feed, Front Seats,
Right Doors
BLOWER Front Climate Control Fan
LBECLeft Bussed Electrical Center,
Door Modules, Door Locks,
Auxiliary Power Outlet—Rear
Cargo Area and Instrument
Panel
STUD 2Accessory Power/Trailer
Wiring Brake Feed
Fuses Usage
ABS Anti-Lock Brakes
VSES/ECAS Vehicle Stability
IGN A Ignition Power
IGN B Ignition Power
LBEC 1Left Bussed Electrical Center,
Left Doors, Truck Body
Controller, Flasher Module
TRL PARK Parking Lamps Trailer Wiring
RR PARKRight Rear Parking and
Sidemarker Lamps
LR PARKLeft Rear Parking and
Sidemarker Lamps
PARK LP Parking Lamps Relay
STRTR Starter Relay
INTPARK Interior Lamps
STOP LP Stoplamps
TBC BATTTruck Body Controller Battery
Feed
S/ROOF Sunroof
SEO B2 Off-Road Lamps
4WSVent Solenoid
Canister/Quadrasteer Module
Power
RR HVAC Not Used
5-127

Center High-Mounted Stoplamp (CHMSL)
and Cargo Lamp.........................................5-67
Center Passenger Position, Safety Belts.............1-25
Chains, Tire...................................................5-90
Check
Engine Light...............................................3-44
Checking Things Under the Hood......................5-12
Chemical Paint Spotting.................................5-119
Child Restraints
Child Restraint Systems...............................1-39
Infants and Young Children...........................1-35
Lower Anchorages and Top Tethers
for Children (LATCH System).....................1-47
Older Children.............................................1-33
Securing a Child Restraint Designed
for the LATCH System..............................1-49
Securing a Child Restraint in a Center
Rear Seat Position...................................1-52
Securing a Child Restraint in a Rear
Outside Seat Position...............................1-50
Securing a Child Restraint in the Center
Front Seat Position...................................1-53
Securing a Child Restraint in the Right
Front Seat Position (Crew Cab)..................1-54
Securing a Child Restraint in the
Right Front Seat Position (Regular
and Extended Cab)..........................1-56, 1-62
Top Strap...................................................1-43
Top Strap Anchor Location............................1-45
Where to Put the Restraint...........................1-42Chime Level Adjustment.................................3-127
Cigarette Lighter.............................................3-20
Cleaning
Aluminum or Chrome-Plated Wheels.............5-117
Exterior Lamps/Lenses................................5-116
Fabric/Carpet............................................5-113
Finish Care...............................................5-116
Glass Surfaces..........................................5-115
Instrument Panel........................................5-115
Interior Plastic Components.........................5-115
Leather....................................................5-114
Tires........................................................5-118
Underbody Maintenance.............................5-119
Vinyl........................................................5-114
Washing Your Vehicle.................................5-116
Weatherstrips............................................5-115
Windshield and Wiper Blades......................5-117
Climate Control System...................................3-21
Dual..........................................................3-22
Dual Automatic............................................3-25
Outlet Adjustment........................................3-30
Clutch, Hydraulic.............................................5-34
Coinholder(s)..................................................2-70
Comfort Guides, Rear Safety Belt.....................1-30
Content Theft-Deterrent....................................2-19
Control of a Vehicle.......................................... 4-5
Coolant
Engine Temperature Gage............................3-42
Heater, Engine............................................2-25
Surge Tank Pressure Cap.............................5-37
3

E
Electrical System
Add-On Equipment.....................................5-121
Center Instrument Panel Fuse Block.............5-124
Fuses and Circuit Breakers.........................5-122
Instrument Panel Fuse Block.......................5-122
Power Windows and Other Power Options....5-122
Underhood Fuse Block...............................5-125
Windshield Wiper Fuses.............................5-121
Engine
Air Cleaner/Filter.........................................5-25
Battery.......................................................5-52
Check and Service Engine Soon Light............3-44
Coolant......................................................5-35
Coolant Heater............................................2-25
Coolant Temperature Gage...........................3-42
Engine Compartment Overview......................5-14
Exhaust.....................................................2-53
Fan Noise..................................................5-45
Oil .............................................................5-20
Overheated Protection Operating Mode...........5-39
Overheating................................................5-37
Starting......................................................2-23
Entry Lighting.................................................3-18
Event Data Recorders (EDR)............................. 7-9
Exit Lighting...................................................3-18
Extender, Safety Belt.......................................1-32
F
Filter
Engine Air Cleaner......................................5-25
Finish Damage.............................................5-118
Fixed Mast Antenna.......................................3-127
Flash-to-Pass................................................... 3-9
Flat Tire........................................................5-91
Flat Tire, Changing.........................................5-92
Flat Tire, Storing...........................................5-109
Fluid
Automatic Transmission........................5-27, 5-30
Manual Transmission....................................5-33
Power Steering...........................................5-46
Windshield Washer......................................5-48
Fog Lamps....................................................3-16
Four-Wheel Drive....................................2-37, 5-58
Four-Wheel-Drive Light....................................3-48
Front Axle......................................................5-60
Front Reading Lamps......................................3-18
Front Storage Area.........................................2-71
Fuel............................................................... 5-6
Additives...................................................... 5-7
California Fuel.............................................. 5-7
E-85 (85% Ethanol)....................................... 5-8
Filling a Portable Fuel Container....................5-12
Filling Your Tank..........................................5-10
Fuels in Foreign Countries.............................. 5-9
Gage.........................................................3-49
Gasoline Octane........................................... 5-6
5

Fuel (cont.)
Gasoline Specications.................................. 5-7
Low Warning Light.......................................3-50
Fuses
Center Instrument Panel Fuse Block.............5-124
Fuses and Circuit Breakers.........................5-122
Instrument Panel Fuse Block.......................5-122
Underhood Fuse Block...............................5-125
Windshield Wiper.......................................5-121
G
Gage
Engine Coolant Temperature.........................3-42
Fuel..........................................................3-49
Oil Pressure...............................................3-47
Speedometer..............................................3-33
Tachometer.................................................3-33
Transmission Temperature.............................3-43
Voltmeter Gage...........................................3-38
Garage Door Opener.......................................2-66
Gasoline
Octane........................................................ 5-6
Specications............................................... 5-7
Glove Box.....................................................2-70
GM Mobility Reimbursement Program.................. 7-5
H
Hazard Warning Flashers................................... 3-6
Head Restraints............................................... 1-8
Headlamps............................................3-13, 5-63
Automatic Headlamp System.........................3-15
Bulb Replacement.......................................5-62
Daytime Running Lamps...............................3-14
Flash-to-Pass............................................... 3-9
Front Turn Signal, Sidemarker and
Daytime Running Lamps...........................5-64
Halogen Bulbs............................................5-62
High/Low Beam Changer................................ 3-9
On Reminder..............................................3-14
Pickup Box Identication and Fender
Marker Lamps.........................................5-69
Roof Marker Lamps.....................................5-65
Heated Seats................................................... 1-5
Heater...................................................3-21, 3-22
Heater...........................................................3-25
Highbeam On Light.........................................3-48
Highway Hypnosis...........................................4-42
Hill and Mountain Roads..................................4-42
HomeLink
®Transmitter....................................2-66
HomeLink®Transmitter, Programming................2-67
Hood
Checking Things Under................................5-12
Release.....................................................5-13
6