2007 GMC ACADIA trailer

Driving on Grades
Your vehicle is designed primarily as a passenger
and load carrying vehicle. If you tow a trailer,
your vehicle will require more frequent
maintenance due to the additional load. Because
of the added load of the trailer, your vehicle’s
engine may overheat on hot days, when going up
a long or steep grade with a trailer. If the engine
coolant temperature gage indicates overheating,
turn off the air conditioning to reduce engine load,
pull off the road and stop in a safe spot.
Reduce speed and shift to a lower gear before
you start down a long or steep downgrade. If you
don’t shift down, you might have to use your
brakes so much that they would get hot and no
longer work well.
On a long uphill grade, shift down and reduce
your speed to around 55 mph (88 km/h) to reduce
the possibility of the engine and the transmission
overheating.
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).
When parking uphill, turn your wheels away
from the curb. When parking downhill,
turn your wheels into the curb.
2. Have someone place chocks behind the
trailer wheels.
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3. When the 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 into 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. SeeScheduled
Maintenance on page 502for more information.
Things that are especially important in trailer
operation are automatic transmission uid
(don’t overll), engine oil, axle lubricant, drive
belt, cooling system and brake system. Each of
these is covered in this manual, and the Index will
help you nd them quickly. If you’re trailering,
it’s a good idea to review this information before
you start your trip.
Check periodically to see that all hitch nuts and
bolts are tight.
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Trailer Wiring Harness
Your vehicle is equipped with the following wiring
harness for towing a trailer.
Basic Trailer Wiring
The trailer wiring harness, with a seven-pin
connector, is located at the rear of the vehicle
and is tied to the vehicle’s frame. The harness
connector can be plugged into a seven-pin
universal heavy-duty trailer connector available
through your dealer/retailer.
The seven-wire harness contains the following
trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Red: Battery Feed*
Dark Blue: Trailer Brake*
*The fuses for these two circuits are installed in
the underhood electrical center, but the wires
are not connected. They should be connected by
your dealer/retailer or a qualied service center.
If you are charging a remote (non-vehicle) battery,
press the tow/haul mode button located at the
end of the shift lever. This will boost the vehicle
system voltage and properly charge the battery.
If the trailer is too light for tow/haul mode, you can
turn on the headlamps (Non-HID only) as a
second way to boost the vehicle system and
charge the battery.
Engine Cooling When Trailer Towing
Your cooling system may temporarily overheat
during severe operating conditions. SeeEngine
Overheating on page 410.
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Gasoline Octane
Use regular unleaded gasoline with a posted
octane rating of 87 or higher. For best performance
or trailer towing, you could choose to use middle
grade 89 octane unleaded gasoline. If the
octane rating is less than 87, you might notice
an audible knocking noise when you drive,
commonly referred to as spark knock. If this
occurs, use a gasoline rated at 87 octane or higher
as soon as possible. If you are using gasoline
rated at 87 octane or higher and you hear heavy
knocking, the engine needs service.
Gasoline Specications
At a minimum, gasoline should meet ASTM
specication D 4814 in the United States or
CAN/CGSB-3.5 or 3.511 in Canada. Some
gasolines contain an octane-enhancing additive
called methylcyclopentadienyl manganese
tricarbonyl (MMT). We recommend against the
use of gasolines containing MMT. SeeAdditives
on page 389for additional information.
California Fuel
If your vehicle is certied to meet California
Emissions Standards, it is designed to operate
on fuels that meet California specications.
See the underhood emission control label.
If this fuel is not available in states adopting
California emissions standards, your vehicle will
operate satisfactorily on fuels meeting federal
specications, but emission control system
performance might be affected. The malfunction
indicator lamp could turn on and your vehicle might
fail a smog-check test. SeeMalfunction Indicator
Lamp on page 226. If this occurs, return to
your authorized dealer/retailer for diagnosis.
If it is determined that the condition is caused
by the type of fuel used, repairs might not
be covered by your warranty.
388

Automatic Transmission Fluid
When to Check and Change Automatic
Transmission Fluid
A good time to check the automatic transmission
uid level is when the engine oil is changed.
Change the uid at the intervals listed inAdditional
Required Services on page 504, and be sure to
use the transmission uid listed inRecommended
Fluids and Lubricants on page 511.
How to Check Automatic Transmission
Fluid
Because this operation can be a little difficult, you
may choose to have this done at the dealer/retailer
service department.
If you do it yourself, be sure to follow all the
instructions here, or you could get a false reading
on the dipstick.Notice:Too much or too little uid can
damage your transmission. Too much can
mean that some of the uid could come out
and fall on hot engine parts or exhaust system
parts, starting a re. Too little uid could
cause the transmission to overheat. Be sure to
get an accurate reading if you check your
transmission uid.
Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above
90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should be at
normal operating temperature, which is 180°F to
200°F (82°C to 93°C).
Get the vehicle warmed up by driving about
15 miles (24 km) when outside temperatures are
above 50°F (10°C). If it is colder than 50°F (10°C),
you may have to drive longer.
404

CAUTION: (Continued)
If you keep driving when the vehicles
engine is overheated, the liquids in it can
catch re. You or others could be badly
burned. Stop your engine if it overheats,
and get out of the vehicle until the engine
is cool.
SeeOverheated Engine Protection
Operating Mode on page 412for
information on driving to a safe place in
an emergency.
Notice:If your engine catches re because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would not
be covered by your warranty. SeeOverheated
Engine Protection Operating Mode on page 412
for information on driving to a safe place in an
emergency.
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.
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 LOW (L).
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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, 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 vehicle until 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
This emergency operating mode lets your vehicle
be driven to a safe place in an emergency situation.
If an overheated engine condition exists, an
overheat protection mode which alternates ring
groups of cylinders helps prevent engine damage.
In this mode, there is a signicant loss in power and
engine performance. The temperature gage
indicates an overheat condition exists. 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 on page 397.
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Fuses Usage
LT PRK Left Parking Lamp
RT PRK Right Parking Lamp
TRLR PRK
LAMPTrailer Parking Lamps
AIRBAG Airbag System
PCM IGN Powertrain Control Module Ignition
AFS Adaptive Forward Lighting System
TRANS Transmission
REAR
CAMERARear Camera
EMISSION 1 Anti-lock Brakes System 2
TRLR BRK Trailer Brake
AWD All-Wheel-Drive System
TRLR PWR Trailer Power
EVEN COILS Even Injector Coils
RR HVAC Rear Climate Control System
SPARE Spare
ODD COILS Odd Injector Coils
SPARE Spare
LT HI BEAM Left High-Beam Headlamp
SPARE Spare
LT TRLR
STOP/TRNTrailer Left Stoplamp and Turn
Signal
EMISSION 2 Emission 2Fuses Usage
ECM Engine Control Module
RT HI BEAM Right High-Beam Headlamp
RVC SNSR Regulated Voltage Control Sensor
RT TRLR
STOP/TRNTrailer Right Stoplamp and Turn
Signal
ECM 1 Engine Control Module 1
SPARE Spare
WPR/WSW Windshield Wiper/Washer
SPARE Spare
PWR OUTLET Power Outlet
AUX POWER Auxiliary Power
RT LO BEAM Right Low-Beam Headlamp
RR APO Rear Accessory Power Outlet
LT LO BEAM Left Low-Beam Headlamp
TCM Transmission Control Module
TRLR BCK/UP Trailer Back-up Lamps
HTD MIR Heated Outside Rearview Mirror
ABS MTR Anti-lock Brake System Motor
FOG LAMP Fog Lamps
HORN Horn
A/C CLTCH Air Conditioning Clutch
FUEL PUMP Fuel Pump
SPARE Spare
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