2008 GMC ENVOY cooling

Entry Lighting
The vehicle has entry lighting.
When any door is opened, the dome lamps come on as
long as the dome override lamp override button is not
pressed in. When all the doors are closed, the lamps
stay on for a short period of time and then turn off
automatically. If you use the Remote Keyless Entry (RKE)
transmitter to unlock the vehicle, the interior lamps come
on for a short time whether or not the dome lamp override
is on.
Exit Lighting
With exit lighting, the interior lamps come on when you
remove the key from the ignition. If the dome override
is off, these lamps stay on for a short period of time
and then go out.
Reading Lamps
The reading lamps are located in the front console.
Press the lens on the lamps to turn the reading lamps
on or off.
Electric Power Management
The vehicle has Electric Power Management (EPM)
that estimates the battery’s temperature and state
of charge. It then adjusts the voltage for best
performance and extended life of the battery.
When the battery’s state of charge is low, the voltage is
raised slightly to quickly put the charge back in. When
the state of charge is high, the voltage is lowered slightly
to prevent overcharging. If the vehicle has a voltmeter
gage or a voltage display on the Driver Information
Center (DIC), you may see the voltage move up
or down. This is normal. If there is a problem, an
alert will be displayed.
The battery can be discharged at idle if the electrical
loads are very high. This is true for all vehicles. This is
because the generator (alternator) may not be spinning
fast enough at idle to produce all the power that is
needed for very high electrical loads.
A high electrical load occurs when several of the
following loads are on: headlamps, high beams, fog
lamps, rear window defogger, climate control fan at
high speed, heated seats, engine cooling fans, trailer
loads, and loads plugged into accessory power outlets.
3-18

Climate Controls
Dual Climate Control System
With this system you can control the heating, cooling,
and ventilation for your vehicle.
9(Fan):Turn the left knob clockwise or
counterclockwise to increase or decrease the
fan speed. If the knob is in off mode, outside air still
enters the vehicle, and is directed based on the position
of the mode knob. The temperature can still be adjusted
using the temperature knob.
Turn the right knob clockwise or counterclockwise to
direct the airow inside of your vehicle.To change the current mode, select one of the following:
H(Vent):This mode directs air to the instrument
panel outlets.
)(Bi-Level):This mode directs about half of the air
to the instrument panel outlets; then directs most of
the remaining air to the oor outlets. A little air is
directed toward the windshield and the side window
outlets. Cooler air is directed to the upper vents
and warmer air to the oor outlets.
6(Floor):This mode directs most of the air to the
oor outlets with a little air directed to the windshield
and the side window outlets. The recirculation button
cannot be selected while in oor mode.
@(Recirculation):Recirculation mode is used to
recirculate the air inside of your vehicle. When this button
is pressed, an indicator light in the button will come on
to let you know that it is active. Use this mode to help
prevent outside odors and/or dust from entering your
vehicle or to help cool the air inside of your vehicle more
quickly. The air conditioning compressor will also come
on when this mode is activated. While in recirculation
mode, the windows may fog when the weather is cold
and damp. To clear the fog, select either the defog or
defrost mode and increase fan speed.
Defog and defrost modes are described later in this
section.
3-21

Rear Window Defogger
If your vehicle has the rear window defogger a warming
grid is used to remove fog on the rear window.
<(Rear):Press this button to turn the rear window
defogger on or off. An indicator light in the button
will come on to let you know that the rear window
defogger is active. The rear window defogger will
automatically turn off approximately ten minutes
after the button is pressed.
If your vehicle has heated mirrors, this button will
activate them.
Notice:Do not use anything sharp on the inside of
the rear window. If you do, you could cut or damage
the warming grid, and the repairs would not be
covered by your warranty. Do not attach a temporary
vehicle license, tape, a decal or anything similar to
the defogger grid.
Dual Automatic Climate Control
System
With this system you can control the heating, cooling
and ventilation for your vehicle. When your vehicle
is rst started and the climate control system is on,
or if the climate control system has been turned on,
the display will show the driver’s temperature setting for
ve seconds. Then it will show the outside temperature.
3-23

Automatic Operation
AUTO (Automatic):When automatic operation is
active, the system will control the inside temperature,
the air delivery mode, and the fan speed.
Use the steps below to place the entire system in
automatic mode:
1. Press the AUTO button.
When AUTO is selected, the air conditioning
operation and air outlet mode will be automatically
controlled. The air conditioning compressor will
run continuously when the outside temperature
is over approximately 40°F (4°C). The air inlet will
normally be set to outside air. If it’s hot outside,
the air inlet will automatically switch to recirculate
inside air to help quickly cool down your vehicle.
2. Set the driver’s and passenger’s temperature.
To nd your comfort setting, start with a 72°F (22°C)
temperature setting and allow about 20 minutes for
the system to adjust. Turn the driver’s or passenger’s
side temperature knob to adjust the temperature
setting as necessary. If you choose the temperature
setting of 60°F (15°C), the system will remain at
the maximum cooling setting. If you choose the
temperature setting of 90°F (32°C), the system will
remain at the maximum heat setting. Choosing either
maximum setting may not cause the vehicle to heat
or cool any faster.
Manual Operation
To change the current setting, select one of the
following:
w9x(Fan):This button allows you to manually
adjust the fan speed. Press the up arrow to increase fan
speed and the down arrow to decrease fan speed. The
display will change to show you the selected fan speed
and the driver’s side temperature setting for ve seconds.
C(Mode):Press this button to manually change the
direction of the airow in your vehicle. Keep pressing the
button until the desired mode appears on the display.
The display will change to show you the selected
air delivery mode and the driver’s temperature setting
for ve seconds.
H(Vent):This mode directs air to the instrument
panel outlets.
)(Bi-Level):This mode directs approximately half
of the air to the instrument panel outlets, then directs the
remaining air to the oor outlets. A little air is directed
toward the windshield and the side window outlets.
Cooler air is directed to the upper outlets and warmer
air to the oor outlets.
3-25

CHECK TIRE PRESSURE
This message displays when the pressure in one or
more of the vehicle’s tires needs to be checked. If a tire
pressure message appears on the DIC, stop as soon
as you can. Have the tire pressures checked and set to
those shown on the Tire Loading Information label.
SeeTires on page 5-57,Loading Your Vehicle on
page 4-34, andInflation - Tire Pressure on page 5-64.
The DIC also shows the tire pressure values. See
DIC Operation and Displays on page 3-50. If the tire
pressure is low, the low tire pressure warning light
comes on. SeeTire Pressure Light on page 3-41.
CHECK WASHER FLUID
This message displays if the washer uid level is low.
Adding washer uid to the windshield washer uid
reservoir clears this message. SeeWindshield Washer
Fluid on page 5-37. This message clears itself after
10 seconds, or you can manually clear it from the
DIC display.
CURB VIEW ACTIVATED
This message displays when the passenger outside
rearview mirror moves into the curb view position.
SeeOutside Curb View Assist Mirror on page 2-47
for more information.
DRIVER DOOR AJAR
This message displays and a chime sounds if the driver
door is not fully closed. Stop and turn off the vehicle,
check the door for obstructions, and close the door again.
Check to see if the message still appears on the DIC.
ENGINE COOLANT HOT/ENGINE
OVERHEATED
Notice:If you drive your vehicle while the engine
is overheating, severe engine damage may occur.
If an overheat warning appears on the instrument
panel cluster and/or DIC, stop the vehicle as soon as
possible. Do not increase the engine speed above
normal idling speed. SeeEngine Overheating
on page 5-28for more information.
This message displays and a chime sounds if the
cooling system temperature gets hot. SeeEngine
Overheating on page 5-28for the proper course of
action. This message clears when the coolant
temperature drops to a safe operating temperature.
FUEL LEVEL LOW
This message displays and a chime sounds if the fuel
level is low. Refuel as soon as possible. SeeLow
Fuel Warning Light on page 3-49,Filling the Tank on
page 5-8, andFuel on page 5-5for more information.
3-54

Driving in Water
{CAUTION:
Driving through rushing water can be
dangerous. Deep water can sweep your vehicle
downstream and you and your passengers
could drown. If it is only shallow water, it can
still wash away the ground from under your
tires, and you could lose traction and roll the
vehicle over. Do not drive through rushing
water.
Heavy rain can mean ash ooding, and ood waters
demand extreme caution.
Find out how deep the water is before you drive through
it. If it is deep enough to cover the wheel hubs, axles,
or exhaust pipe, do not try it — you probably will not get
through. Also, water that deep can damage the axle
and other vehicle parts.If the water is not too deep, drive slowly through it.
At faster speeds, water splashes on the ignition system
and your vehicle can stall. Stalling can also occur if you
get the tailpipe under water. And, as long as the tailpipe
is under water, you will never be able to start the engine.
When you go through water, remember that when the
brakes get wet, it may take you longer to stop.
SeeDriving in Rain and on Wet Roads on page 4-27for
more information on driving through water.
After Off-Road Driving
Remove any brush or debris that has collected on
the underbody, chassis, or under the hood. These
accumulations can be a re hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, wheels, tires, and exhaust system
for damage. Also, check the fuel lines and cooling system
for any leakage.
Your vehicle will require more frequent service due
to off-road use. Refer to the Maintenance Schedule
for additional information.
4-25

Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on at or rolling terrain. Tips for driving
in these conditions include:
Keep your vehicle serviced and in good shape.
Check all uid levels and brakes, tires, cooling
system, and transmission.
Going down steep or long hills, shift to a
lower gear.
{CAUTION:
If you do not shift down, the brakes could get
so hot that they would not work well. You
would then have poor braking or even none
going down a hill. You could crash. Shift down
to let the engine assist the brakes on a steep
downhill slope.
{CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. The brakes will have
to do all the work of slowing down and they
could get so hot that they would not work well.
You would then have poor braking or even
none going down a hill. You could crash.
Always have the engine running and your
vehicle in gear when you go downhill.
Stay in your own lane. Do not swing wide or cut
across the center of the road. Drive at speeds
that let you stay in your own lane.
Top of hills: Be alert — something could be in your
lane (stalled car, accident).
Pay attention to special road signs (falling rocks
area, winding roads, long grades, passing or
no-passing zones) and take appropriate action.
SeeOff-Road Driving on page 4-13for information
about driving off-road.
4-29

Driving with a Trailer
{CAUTION:
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon monoxide
(CO) could come into your vehicle. You can not
see or smell CO. It can cause unconsciousness
or death. SeeEngine Exhaust on page 2-37.
To maximize your safety when towing a trailer:
Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
Keep the rear-most windows closed.
If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main heating
or cooling system on and with the fan on
any speed. This will bring fresh, outside air
into your vehicle. Do not use the climate
control setting for maximum air because it
only recirculates the air inside your vehicle.
SeeDual Climate Control System on
page 3-21.Towing a trailer requires a certain amount of
experience. Before setting out for the open road, you’ll
want to get to know your rig. Acquaint yourself with the
feel of handling and braking with the added weight of the
trailer. And always keep in mind that the vehicle you are
driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connection, lamps,
tires and mirror adjustment. If the trailer has electric
brakes, start your vehicle and trailer moving and then
apply the trailer brake controller by hand to be sure
the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that
the load is secure, and that the lamps and any trailer
brakes are still working.
Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving your vehicle without a trailer.
This can help you avoid situations that require
heavy braking and sudden turns.
4-52