2003 GMC ENVOY heating

Liftgate/Liftglass
{CAUTION:
It can be dangerous to drive with the liftgate or
liftglass open because carbon monoxide (CO)
gas can come into your vehicle. You can't see
or smell CO. It can cause unconsciousness
and even death. If you must drive with the
liftgate open or if electrical wiring or other
cable connections must pass through the seal
between the body and the liftgate or liftglass:
·Make sure all other windows are shut.
·Turn the fan on your heating or cooling
system to its highest speed and select the
control setting that will force outside air
into your vehicle. See ªClimate Control
Systemº in the Index.
·If you have air outlets on or under the
instrument panel, open them all the way.
See ªEngine Exhaustº in the Index.
Liftgate Release
To unlock the liftgate, you may use the power door
locks or the keyless entry system described earlier.
On some vehicles the liftglass will also unlock when the
liftgate is unlocked. Press the pushbutton on the
liftglass to open it.
To open the entire liftgate, lift the handle located in the
center of the liftgate. If you open the liftgate, the
liftgate module will lock the liftglass after a one to two
second delay.
Emergency Release for Opening
Liftgate
1. Remove the trim plug to expose the access hole in
the trim panel.
2. Use a tool to reach through the access hole in the
trim panel.
3. Pry the left release lever up to the unlock position.
Pry the right release lever up to unlatch the liftgate.
4. Reattach the trim plug.
2-13

Certain electrical accessories may not be compatible
with the accessory power outlet and could result
in blown vehicle or adaptor fuses. If you experience a
problem, see your dealer for additional information
on the accessory power outlets.
Notice:Adding some electrical equipment to your
vehicle can damage it or keep other things from
working as they should. This wouldn't be covered by
your warranty. Check with your dealer before
adding electrical equipment, and never use anything
that exceeds the amperage rating.
When adding electrical equipment, be sure to follow the
proper installation instructions included with the
equipment.
Notice:Power outlets are designed for accessory
plugs only. Do not hang any type of accessory
or accessory bracket from the plug. Improper use of
the power outlet can cause damage not covered
by your warranty.
Ashtrays and Cigarette Lighter
Your vehicle may have this feature. The ashtray is
removable and ®ts into the front cupholder.
Notice:Don't put papers or other ¯ammable
items into your ashtrays. Hot cigarettes or other
smoking materials could ignite them, causing
a damaging ®re.
To remove the ashtray, pull the covered bin out of the
cupholder.
To use the lighter, press it in all the way, and let go.
When it's ready, it will pop back out by itself.
Notice:Don't hold a cigarette lighter in with your
hand while it is heating. If you do, it won't be able to
back away from the heating element when it's
ready. That can make it overheat, damaging the
lighter and the heating element.
3-20

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 will still enter the
vehicle, and will be 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 air¯ow 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.
h(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 blend or defrost mode and increase
fan speed. Recirculation mode shuts off when the
engine is turned off.
3-21

Rear Window Defogger
Your vehicle may have this feature. The lines you see
on the rear window warm the glass.
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 is equipped with heated mirrors, this
button will activate them.
Notice:Don't use anything sharp on the inside of
the rear window. If you do, you could cut or damage
the warming grid, and the repairs wouldn't be
covered by your warranty. Do not attach a temporary
vehicle license, tape, a decal or anything similar
to the defogger grid.
Outlet Adjustment
Use the air outlets located in the center and on the side
of your instrument panel to direct the air¯ow.
Ventilation System
For mild outside temperatures when little heating or
cooling is needed, use the vent setting to direct outside
air through your vehicle.
Your vehicle's ventilation system supplies outside air to
the inside of your vehicle when it is moving. With the
side windows closed, air will ¯ow into the front air inlet
grilles, through the vehicle and out the air exhaust
valves.
Outside air will also enter the vehicle when the heater
or the air conditioning is running, unless you have
selected recirculation mode.
3-23

Operation Tips
·
Keep the hood and front air inlets free of ice, snow,
or any other obstruction (such as leaves). The
heater and defroster will work far better, reducing
the chance of fogging the inside of your windows.
·When you enter a vehicle in cold weather, turn the
fan knob all the way to the right for a few moments
before driving. This helps clear the intake ducts
of snow and moisture, and reduces the chance of
fogging the inside of your window.
·Keep the air path under the front seats clear of
objects. This helps air to circulate throughout
your vehicle.
·Adding outside equipment to the front of your
vehicle, such as hood-air de¯ectors, may affect the
performance of the heating and air conditioning
system. Check with your dealer before adding
equipment to the outside of your vehicle.
Dual Automatic Climate Control
System
Your vehicle may have the optional 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.
9(Off):Press this button to turn off the entire climate
control system. Outside air will still enter the vehicle,
and will be directed to the ¯oor. Press the AUTO button,
the mode button, the fan arrows, or either temperature
knob to turn the system on.
3-24

Outlet Adjustment
Use the air outlets located in the center and on the side
of your instrument panel to direct the air¯ow.
Ventilation System
For mild outside temperatures when little heating or
cooling is needed, use the vent setting to direct outside
air through your vehicle.
Your vehicle's ventilation system supplies outside air to
the inside of your vehicle when it is moving. With the
side windows closed, air will ¯ow into the front air inlet
grilles, through the vehicle and out the air exhaust
valves.
Outside air will also enter the vehicle when the heater
or the air conditioning compressor is running, unless you
have pressed the recirculation button.
Operation Tips
·
Keep the hood and front air inlets free of ice, snow,
or any other obstruction (such as leaves). The
heater and defroster will work far better, reducing
the chance of fogging the inside of your windows.
·When you enter a vehicle in cold weather, turn the
fan knob all the way to the right for a few moments
before driving. This helps clear the intake ducts
of snow and moisture, and reduces the chance of
fogging the inside of your window.
·Keep the air path under the front seats clear of
objects. This helps air to circulate throughout
your vehicle.
·Adding outside equipment to the front of your
vehicle, such as hood-air de¯ectors, may affect the
performance of the heating and air conditioning
system. Check with your dealer before adding
equipment to the outside of your vehicle.
3-28

Anti-Lock Brake System
Warning Light
With the anti-lock brake
system, this light will come
on when you start your
engine and may stay on for
several seconds. That's
normal. A chime may also
sound when the light
comes on.
If the light stays on, or comes on when you're driving,
your vehicle needs service. If the regular brake
system warning light isn't on, you still have brakes, but
you don't have anti-lock brakes. If the regular brake
system warning light is also on, you don't have anti-lock
brakes and there's a problem with your regular
brakes. See
Brake System Warning Light on page 3-39earlier in this section.
The anti-lock brake system warning light should come
on brie¯y when you turn the ignition key to RUN. If
the light doesn't come on then, have it ®xed so it will be
ready to warn you if there is a problem.
Engine Coolant Temperature Gage
This gage shows the engine coolant temperature. If the
gage pointer moves into the red area, it means that
your engine coolant has overheated. If you have been
operating your vehicle under normal driving conditions,
you should pull off the road, stop your vehicle and
turn off the engine as soon as possible.
See
Engine Overheating on page 5-27for more
information.
United StatesCanada
3-41

Electronically Controlled Air
Suspension System
Your vehicle may be equipped with an electronically
controlled air suspension system that automatically
keeps your vehicle level as you load and unload. The
system includes a compressor, two height sensors
and two air springs supporting the rear axle.
The system also has an internal clock to prevent
overheating. If the system overheats, all leveling function
stops until the system cools down. During this time,
the indicator light on the air in¯ator system will be
¯ashing.
The ignition has to be on for the system to in¯ate, in
order to raise the vehicle to the standard ride height after
loading. The system can lower the vehicle to the
standard ride height after unloading with the ignition on
and also for up to 30 minutes after the ignition has
been turned off.
You may hear the compressor operating when you load
your vehicle, and periodically as the system adjusts
the vehicle to the standard ride height.Load leveling will not function normally with the in¯ator
hose attached to the in¯ator outlet. Remove the
in¯ator hose from the outlet during loading and
unloading.
If the vehicle is parked for an extended period of time,
some bleed down of the suspension is normal. Upon
starting the vehicle, proper height will be achieved.
Overload Protection
The air suspension system is equipped with overload
protection. Overload protection is designed to protect the
air suspension system, and it is an indicator to the
driver that the vehicle is overloaded. When the overload
protection mode is on, it will not allow damage to the
air compressor. However, do not overload the vehicle.
See
Loading Your Vehicle on page 4-47.
If the suspension remains at a low height, the rear axle
load has exceeded GAWR (Gross Axle Weight
Rating). When the overload protection mode is activated,
the compressor operates for about 30 seconds to one
minute without raising the vehicle depending on the
amount of overload. This will continue each time
the ignition is turned on until the rear axle load is
reduced below GAWR.
4-49