2003 GMC SONOMA open hood

Engine Coolant Heater
Your vehicle may be equipped with this feature.
In very cold weather, 0°F(–18°C) or colder, the engine
coolant heater can help. You’ll get easier starting and
better fuel economy during engine warm-up. Usually, the
coolant heater should be plugged in a minimum of four
hours prior to starting your vehicle. At temperatures
above 32°F(0°C), use of the coolant heater is not
required.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located in the engine compartment behind
the underhood fuse block on the driver’s side of
the vehicle.
3. Plug it into a normal, grounded 110–volt AC outlet.
{CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the
wrong kind of extension cord could overheat
and cause afire. You could be seriously
injured. Plug the cord into a properly grounded
three-prong 110-volt AC outlet. If the cord
won’t reach, use a heavy-duty three-prong
extension cord rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and
store the cord as it was before to keep it away
from moving engine parts. If you don’t, it could be
damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead
of trying to list everything here, we ask that you contact
your dealer in the area where you’ll be parking your
vehicle. The dealer can give you the best advice for that
particular area.
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2003 - Sonoma OM

Dome Lamp
The dome lamp will come on when you open any door.
You can also turn the dome lamps on by turning the
instrument panel brightness thumbwheel, located next to
the exterior lamps control, all the way up to the
second notch. In this position, the dome lamps will
remain on whether a door is opened or closed.
You can use the DOME OVERRIDE button, located
below the exterior lamps control, to set the dome lamps
to come on automatically when any door is opened,
or to remain off. To turn the lamps off, press the button
in. With the button in, the dome lamps will remain off
when any door is opened. To return the lamps to
automatic operation, press the button again and return
it to the out position. With the button in this position,
the dome lamps will come on when you open any door.
This will override the illuminated entry feature, unless
you use your remote keyless entry transmitter
(if equipped) to unlock the vehicle.
Battery Rundown Protection
This feature shuts off the dome, courtesy, vanity,
reading, glove box, cargo and underhood lamps if they
are left on for more than 20 minutes when the ignition
is off. This will keep your battery from running down.If the battery rundown protection shuts off the interior
lamps, it may be necessary to do one of the following to
return it to normal operation:
Shut off all lamps and close all doors, or
turn the ignition key to RUN.
Accessory Power Outlets
Your vehicle may be equipped with an accessory
power outlet.
With accessory power outlets you can plug in auxiliary
electrical equipment such as a cellular telephone or
CB radio.
There may be an accessory power outlet located near
the center of the vehicle on the lower part of the
instrument panel. A small cap must be pulled down to
access an accessory power outlet. When not using
an outlet be sure to cover it with the protective cap.
Notice:When using an accessory power outlet,
maximum electrical load must not exceed 20 amps.
Always turn off any electrical equipment when
not in use. Leaving electrical equipment on for
extended periods will drain your battery.
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2003 - Sonoma OM

Filling a Portable Fuel Container
{CAUTION:
Neverll a portable fuel container while it is in
your vehicle. Static electricity discharge from
the container can ignite the gasoline vapor.
You can be badly burned and your vehicle
damaged if this occurs. To help avoid injury
to you and others:
Dispense gasoline only into approved
containers.
Do notll a container while it is inside a
vehicle, in a vehicle’s trunk, pickup bed or
on any surface other than the ground.
Bring thell nozzle in contact with the
inside of thell opening before operating
the nozzle. Contact should be maintained
until thelling is complete.
Don’t smoke while pumping gasoline.
Checking Things Under
the Hood
{CAUTION:
Things that burn can get on hot engine parts
and start are. These include liquids like fuel,
oil, coolant, brakeuid, windshield washer and
otheruids, and plastic or rubber. You or
others could be burned. Be careful not to drop
or spill things that will burn onto a hot engine.
5-8
2003 - Sonoma OM

Hood Release
To open the hood, do the following:
1. Pull the handle
located inside the
vehicle on the lower
left side of the
instrument panel.
2. Lift the hood.3. Release the hood prop from its retainer and put the
hood prop into the slot in the hood.
Before closing the hood, be sure all thefiller caps are
on properly. Then lift the hood to relieve pressure on the
hood prop.
Remove the hood prop from the slot in the hood and
return the prop to its retainer.
Then, pull the hood downfirmly to close. It will latch
when dropped from about 10 to 12 inches (25 to 30 cm)
without pressing on the hood.
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2003 - Sonoma OM

Engine Compartment Overview
When you open the hood on the 2200 L4 engine, you’ll see:
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2003 - Sonoma OM

When you open the hood on the 4300 V6 engine, you’ll see:
A. Battery
B. Coolant Recovery Tank
C. Engine Oil Dipstick
D. Engine Oil Fill
E. Automatic Transmission Dipstick (If Equipped)F. Power Steering Reservoir
G. Brake Master Cylinder Reservoir
H. Engine Air Cleaner/Filter
I. Engine Compartment Fuse Block
J. Windshield Washer Fluid Reservoir
5-12
2003 - Sonoma OM

Engine Overheating
You willfind a coolant temperature gage on your
vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 3-29.
If Steam Is Coming From Your Engine
{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood.
Stay away from the engine if you see or hear
steam coming from it. Just turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
If you keep driving when your engine is
overheated, the liquids in it can catchre. You
or others could be badly burned. Stop your
engine if it overheats, and get out of the
vehicle until the engine is cool.
Notice:If your engine catchesre because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would not be
covered by your warranty.
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2003 - Sonoma OM

If No Steam Is Coming From Your
Engine
If you get an engine overheat warning but see or hear
no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
•Climb a long hill on a hot day.
•Stop after high-speed driving.
•Idle for long periods in traffic.
•Tow a trailer. See“Driving on Grades”under
Towing a Trailer on page 4-51.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL
while stopped. If it is safe to do so, pull off the
road, shift to PARK (P) or NEUTRAL and let the
engine idle.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning doesn’t come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there’s still no sign of steam, idle the engine for three
minutes while you’re parked. Push down the accelerator
until the engine speed is about twice as fast as normal
idle speed for at least three minutes while you’re parked.
If you still have the warning,turn off the engine and get
everyone out of the vehicleuntil it cools down.
You may decide not to lift the hood but to get service
help right away.
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2003 - Sonoma OM