2010 BUICK ENCLAVE trailer

9-50 Driving and Operating
Maintenance When Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See this
manual's Maintenance Schedule or
Index for more information. Things
that are especially important in
trailer operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system and
brake system. Inspect these before
and during the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Engine Cooling When Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. SeeEngine Overheating
on page 10‑18.
Trailer Towing
Three important considerations
have to do with weight:
.The weight of the trailer
.The weight of the trailer tongue
.The total weight on the vehicle's
tires
Weight of the Trailer
How heavy can a trailer safely be?
Speed, altitude, road grades,
outside temperature, special
equipment, and the amount of
tongue weight the vehicle can carry
must be considered. See “Weight of
the Trailer Tongue” later in this
section for more information.
Maximum trailer weight is calculated
assuming only the driver is in the
tow vehicle and it has all the
required trailering equipment.
The weight of additional optional
equipment, passengers and cargo in
the tow vehicle must be subtracted
from the maximum trailer weight.

Driving and Operating 9-51
Use the following chart to determine how much the vehicle can weigh, based upon the vehicle model and options.Vehicle Maximum Trailer Weight *GCWR
Front-Wheel Drive 2,000 lbs (907 kg) 7,500 lbs (3 402 kg)
Front-Wheel Drive, V92 Trailer Towing Package 4,500 lbs (2 041 kg) 9,500 lbs (4 309 kg)
All-Wheel Drive 2,000 lbs (907 kg) 7,700 lbs (3 493 kg)
All-Wheel Drive, V92 Trailer Towing Package 4,500 lbs (2 041 kg) 9,700 lbs (4 400 kg)
*The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for the vehicle should not be
exceeded.
Ask your dealer/retailer for our
trailering information or advice. See
Customer Assistance Offices (US,
Can)
on page 13‑3for more
information.
Weight of the Trailer Tongue
The tongue load (A) of any trailer is
an important weight to measure
because it affects the total gross
weight of the vehicle. The Gross
Vehicle Weight (GVW) includes the
curb weight of the vehicle, any
cargo carried in it, and the people
who will be riding in the vehicle.
If there are a lot of options, equipment, passengers or cargo in
the vehicle, it will reduce the tongue
weight the vehicle can carry, which
will also reduce the trailer weight the
vehicle can tow. If towing a trailer,
the tongue load must be added to
the GVW because the vehicle will
be carrying that weight, too. See
Vehicle Load Limits on page 9‑12

9-52 Driving and Operating
If a weight-carrying hitch or a
weight-distributing hitch is being
used, the trailer tongue (A) should
weigh 10-15 percent of the total
loaded trailer weight (B).
After loading the trailer, weigh the
trailer and then the tongue,
separately, to see if the weights are
proper. If they are not, adjustments
might be made by moving some
items around in the trailer.
Trailering may be limited by the
vehicle's ability to carry tongue
weight. Tongue weight cannot cause
the vehicle to exceed the GVWR(Gross Vehicle Weight Rating) or
the RGAWR (Rear Gross Axle
Weight Rating). The effect of
additional weight may reduce the
trailering capacity more than the
total of the additional weight.
Consider the following example:
A vehicle model base weight is
2 495 kg (5,500 lbs); 1 270 kg
(2,800 lbs) at the front axle and
1 225 kg (2,700 lbs) at the rear axle.
It has a GVWR of 3 266 kg
(7,200 lbs), a RGAWR of 1 814 kg
(4,000 lbs) and a GCWR (Gross
Combination Weight Rating) of
6 350 kg (14,000 lbs). The trailer
rating should be:
Expect tongue weight to be at least
10 percent of trailer weight (386 kg
(850 lbs)) and because the weight isapplied well behind the rear axle,
the effect on the rear axle is greater
than just the weight itself, as much
as 1.5 times as much. The weight at
the rear axle could be 386 kg
(850 lbs) X 1.5 = 578 kg (1,275 lbs).
Since the rear axle already weighs
1 225 kg (2,700 lbs), adding 578 kg
(1,275 lbs) brings the total to
1 803 kg (3,975 lbs). This is very
close to, but within the limit for
RGAWR as well. The vehicle is set
to trailer up to 3 856 kg (8,500 lbs).
If the vehicle has many options and
there is a front seat passenger and
two rear seat passengers with some
luggage and gear in the vehicle as
well. 136 kg (300 lbs) could be
added to the front axle weight and
181 kg (400 lbs) to the rear axle
weight. The vehicle now weighs:

Driving and Operating 9-53
Weight is still below 3 266 kg
(7,200 lbs) and you might think
318 additional kilograms (700 lbs)
should be subtracted from the
trailering capacity to stay within
GCWR limits. The maximum trailer
would only be 3 538 kg (7,800 lbs).
You may go further and think the
tongue weight should be limited to
less than 454 kg (1,000 lbs) to avoid
exceeding GVWR. But the effect on
the rear axle must still be
considered. Because the rear axle
now weighs 1 406 kg (3,100 lbs),
408 kg (900 lbs) can be put on the
rear axle without exceeding
RGAWR. The effect of tongue
weight is about 1.5 times the actual
weight. Dividing the 408 kg (900 lbs)
by 1.5 leaves only 272 kg (600 lbs)
of tongue weight that can be
handled. Since tongue weight is
usually at least 10 percent of total
loaded trailer weight, expect that
the largest trailer the vehicle can
properly handle is 2 722 kg
(6,000 lbs).It is important that the vehicle
does not exceed any of its
ratings
—GCWR, GVWR, RGAWR,
Maximum Trailer Rating or Tongue
Weight. The only way to be sure it is
not exceeding any of these ratings
is to weigh the vehicle and trailer.
Total Weight on the Vehicle's
Tires
Inflate the vehicle's tires to the
upper limit for cold tires. These
numbers can be found on the
Certification label or see Vehicle
Load Limits
on page 9‑12for more
information. Do not go over the
GVW limit for the vehicle, or the
GAWR, including the weight of the
trailer tongue. If using a weight
distributing hitch, do not go over the
rear axle limit before applying the
weight distribution spring bars.
Towing Equipment
Hitches
It is important to have the correct
hitch equipment. Crosswinds, large
trucks going by and rough roads are
a few reasons why the right hitch is
needed.
.The rear bumper on the vehicle
is not intended for hitches. Do
not attach rental hitches or other
bumper-type hitches to it. Use
only a frame-mounted hitch that
does not attach to the bumper.
.Will any holes be made in the
body of the vehicle when the
trailer hitch is installed? If there
are, then be sure to seal the
holes when the hitch is removed.
If the holes are not sealed, dirt,
water, and deadly carbon
monoxide (CO) from the exhaust
may get into the vehicle. See
Engine Exhaust on page 9‑22.

9-54 Driving and Operating
Weight-Distributing Hitches and
Weight Carrying Hitches
A. Body-to-Ground Distance
B. Front of Vehicle
When using a weight-distributing
hitch, the hitch must be adjusted so
that the distance (A) remains the
same both before and after coupling
the trailer to the tow vehicle.
Safety Chains
Always attach chains between the
vehicle and the trailer. Cross the
safety chains under the tongue of
the trailer to help prevent the tongue
from contacting the road if it
becomes separated from the hitch.
Always leave just enough slack so
the rig can turn. Never allow safety
chains to drag on the ground.
Trailer Brakes
A loaded trailer that weighs more
than 450 kg (1,000 lbs) needs to
have its own brake system that is
adequate for the weight of the
trailer. Be sure to read and follow
the instructions for the trailer brakes
so they are installed, adjusted and
maintained properly.
Because the vehicle has antilock
brakes, do not try to tap into the
vehicle's hydraulic brake system.
If you do, both brake systems will
not work well, or at all.
Trailer Wiring Harness
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
.Black: Ground
.Light Green: Back-up Lamps
.Red/Black: Battery Feed
.Dark Blue: Trailer Brake*
*The fuse for this circuit is installed
in the underhood electrical center,
but the wires are not connected.

Driving and Operating 9-55
They should be connected by your
dealer/retailer or a qualified service
center.
If the back-up lamp circuit is not
functional, contact your dealer/
retailer.
If a remote (non-vehicle) battery is
being charged, press the Tow/Haul
mode switch located on the center
console near the climate controls.
This will boost the vehicle system
voltage and properly charge the
battery. If the trailer is too light for
Tow/Haul mode, turn on the
headlamps (Non-HID only) as a
second way to boost the vehicle
system and charge the battery.Electric Trailer Brake Control
Wiring Provisions
These wiring provisions for an
electric trailer brake controller are
included with the vehicle as part of
the trailer wiring package. The
instrument panel contains blunt cut
wires behind the steering column for
the electric trailer brake controller.
The harness contains the following
wires:
.Red/Black: Power Supply
.White: Brake Switch Signal
.Gray: Illumination
.Dark Blue: Trailer Brake Signal
.Black: Ground
The electric trailer brake controller
should be installed by your dealer/
retailer or a qualified service center.
Conversions and
Add-Ons
Add-On Electrical
Equipment
Notice: Do not add anything
electrical to the vehicle unless
you check with your dealer/
retailer first. Some electrical
equipment can damage the
vehicle and the damage would
not be covered by the vehicle's
warranty. Some add-on electrical
equipment can keep other
components from working as
they should.
Add-on equipment can drain the
vehicle battery, even if the vehicle is
not operating.
The vehicle has an airbag system.
Before attempting to add anything
electrical to the vehicle, see
Servicing the Airbag-Equipped
Vehicle
on page 3‑41and Adding
Equipment to the Airbag-Equipped
Vehicle on page 3‑42.

Vehicle Care 10-19
If you do decide to lift the hood ,
make sure the vehicle is parked on
a level surface.
Then check to see if the engine
cooling fans are running. If the
engine is overheating, both fans
should be running. If they are not,
do not continue to run the engine
and have the vehicle serviced.
Notice:Engine damage from
running the engine without
coolant is not covered by the
warranty.
Notice: If the engine catches fire
while driving with no coolant, the
vehicle can be badly damaged.
The costly repairs would not be
covered by the vehicle warranty.
See Overheated Engine
Protection Operating Mode
on
page 10‑20for information on
driving to a safe place in an
emergency.
If Steam Is Coming From The
Engine Compartment
{WARNING
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. 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 the
vehicles engine is overheated,
the liquids in it can catch fire. You
or others could be badly burned.
Stop the engine if it overheats,
and get out of the vehicle until the
engine is cool.
(Continued)
WARNING (Continued)
SeeOverheated Engine
Protection Operating Mode
on
page 10‑20
for information on
driving to a safe place in an
emergency.
If No Steam Is Coming From
The Engine Compartment
If an engine overheat warning is
displayed but no steam can be seen
or heard, the problem may not be
too serious. Sometimes the engine
can get a little too hot when the
vehicle:
.Climbs a long hill on a hot day.
.Stops after high-speed driving.
.Idles for long periods in traffic.
.Tows a trailer.

10-20 Vehicle Care
If the overheat warning is displayed
with no sign of steam:
1. Turn the air conditioning off.
2. Turn the heater on to the highesttemperature and to the highest
fan speed. Open the windows as
necessary.
3. If in a traffic jam, shift to N (Neutral), otherwise, shift to
the highest gear while
driving —D (Drive) or L (Low).
If the temperature overheat gage is
no longer in the overheat zone or an
overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slow
for about 10 minutes. Keep a safe
vehicle distance from the car in front
of you. If the warning does not come
back on, continue to drive normally.
If the warning continues, pull over,
stop, and park the vehicle
right away. If there is no sign of steam, idle the
engine for three minutes while
parked. If the warning is still
displayed, turn off the engine until it
cools down. Also, see
“Overheated
Engine Protection Operating Mode”
next in this section.
Overheated Engine
Protection
Operating Mode
This emergency operating mode lets
the vehicle be driven to a safe place
in an emergency situation. If an
overheated engine condition exists,
an overheat protection mode which
alternates firing groups of cylinders
helps prevent engine damage. In
this mode, there is a significant loss
in power and engine performance.
The temperature gage indicates an
overheat condition exists. Driving
extended distances 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. See
Engine Oil on page 10‑8.
Power Steering Fluid
The power steering fluid reservoir is
located under the engine cover on
the passenger side of the vehicle.
See Engine Compartment Overview
on page 10‑6for reservoir location.