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4. With the coolant surge tank pressure cap off, start
the engine and let it run until you can feel the upper
radiator hose getting hot. Watch out for the
engine cooling fan.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mixture to the coolant surge tank
until the level reaches the FULL COLD mark.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
Engine Fan Noise
If your vehicle is equipped with a clutched engine
cooling fan, when the clutch is engaged, the fan spins
faster to provide more air to cool the engine. In
most everyday driving conditions, the fan is spinning
slower and the clutch is not fully engaged. This improves
fuel economy and reduces fan noise. Under heavy
vehicle loading, trailer towing, and/or high outside
temperatures, the fan speed increases as the clutch
more fully engages, so you may hear an increase in fan
noise. This is normal and should not be mistaken as
the transmission slipping or making extra shifts. It
is merely the cooling system functioning properly. The
fan will slow down when additional cooling is not
required and the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
If your vehicle is equipped with electric cooling fans, you
may hear the fans spinning at low speed during most
everyday driving. The fans may turn off if no cooling is
required. Under heavy vehicle loading, trailer towing,
and/or high outside temperatures, or if you are operating
your air conditioning system, the fans change to high
speed and you may hear an increase in fan noise. This
is normal and indicates that the cooling system is
functioning properly. The fans will change to low speed
when additional cooling is no longer required.
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Page 449 of 536

Each new wheel should have the same load-carrying
capacity, diameter, width, offset and be mounted
the same way as the one it replaces.
If you need to replace any of your wheels, wheel bolts
or wheel nuts, replace them only with new GM
original equipment parts. This way, you will be sure to
have the right wheel, wheel bolts and wheel nuts
for your vehicle.
{CAUTION:
Using the wrong replacement wheels, wheel
bolts or wheel nuts on your vehicle can be
dangerous. It could affect the braking and
handling of your vehicle, make your tires lose
air and make you lose control. You could have
a collision in which you or others could be
injured. Always use the correct wheel, wheel
bolts and wheel nuts for replacement.Notice:The wrong wheel can also cause problems
with bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper height,
vehicle ground clearance and tire or tire chain
clearance to the body and chassis.
SeeChanging a Flat Tire on page 5-78for more
information.
Used Replacement Wheels
{CAUTION:
Putting a used wheel on your vehicle is
dangerous. You cannot know how it has been
used or how far it has been driven. It could fail
suddenly and cause a crash. If you have to
replace a wheel, use a new GM original
equipment wheel.
5-75
Page 489 of 536
Fuses Usage
CRNK Starting System
LO HDLP - RT Headlamp Low Beam - Right
FOG LP Fog Lamp Relay
FOG LP Fog Lamps
HORN Horn Fuse
HORN Horn Relay
W/S WASHWindshield and Rear Window
Washer Pump Relay
W/S WASHWindshield and Rear Window
Washer Pump
INFOOnStar
®/Rear Seat
Entertainment
RADIO AMP Radio Ampli er
RH HID Not Used
EAP Electric Adjustable Pedals
TREC All-Wheel Drive Module
SBA Supplemental Brake Assist
Auxiliary Electric Cooling Fan
Fuse Block
The auxiliary electric
cooling fan fuse block is
located in the engine
compartment on the
driver’s side of the vehicle
next to the underhood
fuse block.
Lift the cover for access to the fuse/relay block.
Fuses Usage
COOL/FAN Cooling Fan
COOL/FAN Cooling Fan Relay Fuse
COOL/FAN Cooling Fan Fuse
Relays Usage
COOL/FAN 1 Cooling Fan Relay 1
COOL/FAN 3 Cooling Fan Relay 3
COOL/FAN 2 Cooling Fan Relay 2
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