1999 CHEVROLET ASTRO cooling

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2-13
Hatch
CAUTION:
It can be dangerous to drive with the rear
swing
-out windows, rear hatch or rear doors
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 rear swing-out windows,
rear hatch or rear doors open or if electrical wiring
or other cable connections must pass through the
seal between the body and the rear swing
-out
windows, rear hatch or rear doors:

Make sure all other windows are shut.

Turn the fan on your heating or cooling
system to its highest speed with the setting
on anything but MAX A/C. That will force
outside air into your vehicle. See ªComfort
Controlsº 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.
Hatch Release (Option)
You can use your key to unlock the hatch and all the
other doors from the outside. Insert the key into the
hatch release button and turn it counterclockwise. All
doors will unlock.
You may also use the Keyless Entry System
described earlier.
The hatch can be opened or closed without a key if the
door lock system is unlocked.
To open the hatch, unlock it, press the button and lift the
handle located in the center of the door.

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2-30
Express-Down Window
The driver's window switch also has an express
-down
feature that allows you to lower it without holding the
window switch. Press and hold the side of the driver's
window switch down marked AUTO for one second to
activate the express
-down feature. The express-down
feature can be interrupted at any time by pressing the up
arrow end of the switch. Lightly tap the switch to open
the window slightly.
Swing-Out Windows
To open your swing-out
windows, pull up on the
latch and push the
window out.
To close the window, pull the latch toward you and push
it down.
CAUTION:
It can be dangerous to drive with the rear
swing
-out windows, rear hatch or rear doors
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 rear swing-out
windows, rear hatch or rear doors open or if
electrical wiring or other cable connections
must pass through the seal between the body
and the rear swing
-out windows, rear hatch or
rear doors:

Make sure all other windows are shut.

Turn the fan on your heating or cooling
system to its highest speed with the setting
on anything but MAX A/C. That will force
outside air into your vehicle. See ªComfort
Controlsº 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.

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3-2
Comfort Controls
This section tells you how to make your air system
work for you. Your comfort control system uses
ozone
-friendly R-134a refrigerant.
With these systems, you can control the heating, cooling
and ventilation in your vehicle. Your vehicle also has a
flow
-through ventilation system described later in
this section.
Heating/Air Conditioning System
If your vehicle has air conditioning, your heating/air
conditioning controls will look like this.Fan Knob
This control has four positions. To increase airflow, turn
the knob toward HI. To decrease airflow, move it
toward LO.
Temperature Knob
This knob is next to the fan knob. It controls the
temperature of the air flowing into your vehicle. Turn
the knob clockwise for warmer air. Turn the knob
counterclockwise for cooler air.
Function Knob
This knob is next to the temperature knob.
OFF: This setting turns the system off.
MAX A/C: This cools the air the fastest, by
recirculating the inside air. Turn the temperature knob
all the way to MAX A/C.
A/C: This setting brings in outside air and cools it.

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3-6
If your vehicle has rear air conditioning, setting it on
LOW may enhance the front A/C performance by
allowing trapped refrigerant in the rear lines to circulate.
The rear air conditioning system will only send cooled
air if the front system is on. It can still be used to
circulate air, even if the front system is off.
When the air conditioning, DEFROST or BLEND is on,
you may notice a slight increase or decrease in engine
speed, due to compressor operation. This is normal
because the system is designed to cycle the compressor
on and off to keep the desired temperature.
Heating
On cold days, use HEATER with the temperature knob
in the red area. Outside air will be brought in through
the floor outlets. The heater works best if you keep your
windows closed while using it.
If you use the optional engine coolant heater before
starting your engine, your heating system will produce
warmer air faster to heat the passenger compartment in
cold weather. See ªEngine Coolant Heaterº in the Index.
Defrosting
Use DEFROST to remove fog or ice from the
windshield quickly in extremely cold conditions. The
temperature knob should be in the red area and the fan
control toward high. The air conditioning compressor
may operate in this setting to dehumidify the air.
The BLEND setting is useful for cold weather with a
large number of passengers or very humid conditions to
help keep the windshield clear.
Ventilation System
For mild outside temperatures when little heating or
cooling is needed, use VENT to direct outside air
through your vehicle. Air will flow through the
instrument panel vents.
Your vehicle's flow
-through ventilation system supplies
outside air to the inside of your vehicle when it is
moving. With the side windows closed, air will flow into
the front air inlet grilles at the base of the windshield,
through the vehicle and out the rear air exhaust valve.
Outside air will also enter the vehicle when the heater or
the air conditioning fan is running.

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4-23

Keep your vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system and
transmission. These parts can work hard on
mountain roads.

Know how to go down hills. The most important
thing to know is this: let your engine do some of the
slowing down. Shift to a lower gear when you go
down a steep or long hill.
CAUTION:
If you don't shift down, your brakes could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a
hill. You could crash. Shift down to let your
engine assist your brakes on a steep
downhill slope.
CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have to
do all the work of slowing down. They could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a hill.
You could crash. Always have your engine running
and your vehicle in gear when you go downhill.

Know how to go uphill. You may want to shift down
to a lower gear. The lower gears help cool your engine
and transmission, and you can climb the hill better.

Stay in your own lane when driving on two
-lane
roads in hills or mountains. Don't swing wide or cut
across the center of the road. Drive at speeds that let
you stay in your own lane.

As you go over the top of a hill, be alert. There could be
something in your lane, like a stalled car or an accident.

You may see highway signs on mountains that warn of
special problems. Examples are long grades, passing or
no
-passing zones, a falling rocks area or winding
roads. Be alert to these and take appropriate action.

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4-35
Your trailer brake system can tap into your vehicle's
hydraulic brake system, except:

Don't tap into your vehicle's brake system if the
trailer's brake system will use more than 0.02 cubic
inch (0.3 cc) of fluid from your vehicle's master
cylinder. If it does, both braking systems won't work
well. You could even lose your brakes.

Will the trailer parts take 3,000 psi (20 650 kPa) of
pressure? If not, the trailer brake system must not be
used with your vehicle.

If everything checks out this far, then make the brake
fluid tap at the port on the master cylinder that sends
fluid to the rear brakes. But don't use copper tubing
for this. If you do, it will bend and finally break off.
Use steel brake tubing.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't see
or smell CO. It can cause unconsciousness or
death. (See ªEngine Exhaustº in the Index.) 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
MAX A/C because it only recirculates the
air inside your vehicle. (See ªComfort
Controlsº in the Index.)

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4-38 Parking on Hills
CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People can
be injured, and both your vehicle and the trailer
can be damaged.
But if you ever have to park your rig on a hill, here's
how to do it:
1. Apply your regular brakes, but don't shift into
PARK (P) yet.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your parking
brake, and shift to PARK (P).
5. Release the regular brakes.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:

Start your engine;

Shift into a gear; and

Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission fluid (don't
overfill), engine oil, axle lubricant, belt, cooling system
and brake system. Each of these is covered in this
manual, and the Index will help you find them quickly.
If you're trailering, it's a good idea to review these
sections before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.

5-
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5-1
Section 5 Problems on the Road
Here you'll find what to do about some problems that can occur on the road.
5
-2 Hazard Warning Flashers
5
-3 Other Warning Devices
5
-3 Jump Starting
5
-7 Towing Your Vehicle
5
-8 Engine Overheating
5
-10 Cooling System5
-18 Engine Fan Noise
5
-18 If a Tire Goes Flat
5
-19 Changing a Flat Tire
5
-32 Compact Spare Tire
5
-33 If You're Stuck: In Sand, Mud, Ice, or Snow