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242 Vehicle Care
When to Change Lubricant
Refer toMaintenance Schedule
0 311 to determine how often to
change the lubricant.
What to Use
Refer to Recommended Fluids and
Lubricants 0321 to determine what
kind of lubricant to use.
Front Axle
When to Check Lubricant
It is not necessary to regularly
check the front axle fluid unless a
leak is suspected or an unusual
noise is heard. A fluid loss could
indicate a problem. Have it
inspected and repaired. This service
can be complex. See your dealer.
Do not directly power wash the
transfer case and/or front/rear axle
output seals. High pressure water
can overcome the seals and
contaminate the fluid. Contaminated
fluid will decrease the life of the
transfer case and/or drive axles and
should be replaced.
Rear Axle
When to Check Lubricant
It is not necessary to regularly
check the rear axle fluid unless a
leak is suspected or an unusual
noise is heard. A fluid loss could
indicate a problem. Have it
inspected and repaired. This service
can be complex. See your dealer.
Do not directly power wash the
transfer case and/or front/rear axle
output seals. High pressure water
can overcome the seals and
contaminate the fluid. Contaminated
fluid will decrease the life of the
transfer case and/or drive axles and
should be replaced.
Starter Switch Check
{Warning
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured. 1. Before starting this check, be
sure there is enough room
around the vehicle.
2. Apply both the parking brake and the regular brake.
Do not use the accelerator
pedal, and be ready to turn off
the engine immediately if it
starts.
3. Try to start the engine in each gear. The vehicle should start
only in P (Park) or N (Neutral).
If the vehicle starts in any other
position, contact your dealer for
service.
Automatic Transmission
Shift Lock Control
Function Check
{Warning
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
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Vehicle Care 243
1. Before starting this check, besure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Apply the parking brake. Be ready to apply the regular
brake immediately if the vehicle
begins to move.
3. With the engine off, turn the ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with
normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Ignition Transmission
Lock Check
While parked, and with the parking
brake set, try to turn the ignition off
in each shift lever position.
.The ignition should turn to off
only when the shift lever is in
P (Park).
. The ignition key should come
out only when the ignition is off. Contact your dealer if service is
required.
Park Brake and P (Park)
Mechanism Check
{Warning
When you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move.
Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake.
. To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.
. To check the P (Park)
mechanism's holding ability:
With the engine running, shift to
P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement
Windshield wiper blades should be
inspected for wear or cracking.
Replacement blades come in
different types and are removed in
different ways. For proper
windshield wiper blade length and
type, see Maintenance
Replacement Parts 0323.
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Headlamp
1. Open the hood.
2. Remove the headlamp bulbcover by turning it
counterclockwise.
3. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly
and pull it straight out.
4. Unplug the electrical connector from the old bulb by releasing
the clip on the bulb socket.
5. Replace the bulb and reverse Steps 1–4 to reinstall.
Turn Signal/Sidemarker/
Parking Lamp
1. Open the hood.
2. Turn the bulb socketcounterclockwise to remove it
from the headlamp assembly
and pull it straight out.
3. Remove the bulb by pulling it straight out of the bulb socket.
4. Replace the bulb and reverse Steps 1–3 to reinstall.
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps
1. Taillamp/Stoplamp/TurnSignal
2. Back-up Lamp
3. Taillamp/Stoplamp/Turn Signal/Sidemarker
1. Open the tailgate.
2. Remove the two rear lamp assembly screws.
3. Pull the rear lamp assembly outboard away from the box
side until the retainers release.
There will be a noise when the
retainers release.
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248 Vehicle Care
4. Pull the rear lamp assemblystraight back to remove it from
the vehicle.
5. Turn the bulb socket counterclockwise.
6. Pull the bulb straight out from the socket.
7. Replace the bulb, then insert the bulb socket into the rear
lamp assembly and turn
clockwise.8. Verify the retainer ring is in theproper position. If the retainer
ring is out of position, it will not
engage. Reset the retainer by
pulling it forward with a tool.
9. Push the rear lamp assembly straight in until it is seated
against the vehicle.
10. Make sure the rear lamp assembly is flush with the
box side.
11. Reinstall the two rear lamp assembly screws.
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp
1. Cargo Lamp Bulbs
2. Center High-MountedStoplamp (CHMSL) Bulb
To replace one of these bulbs:
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Vehicle Care 249
1. Remove the two screws and liftoff the lamp assembly.
2. Turn the bulb socket counterclockwise and pull it
straight out.
3. Pull the bulb straight out from the socket.
4. Replace the bulb and reverse Steps 1-3 to reinstall.
Electrical System
Electrical System
Overload
The vehicle has fuses to protect
against an electrical system
overload. Fuses also protect power
devices in the vehicle.
Replace a bad fuse with a new one
of the identical size and rating.
If there is a problem on the road and
a fuse needs to be replaced, there
is a fuse puller in the Engine
Compartment Fuse Block. Replace
the fuse as soon as possible with
one of the same amperage rating.
Headlamp Wiring
An electrical overload may cause
the lamps to go on and off, or in
some cases to remain off. Have the
headlamp wiring checked right away
if the lamps go on and off or
remain off.
Windshield Wipers
If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop until the motor cools
and will then restart.
Although the circuit is protected
from electrical overload, overload
due to heavy snow or ice may
cause wiper linkage damage.
Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses and Circuit
Breakers
The wiring circuits in the vehicle are
protected from short circuits by
fuses. This greatly reduces the
chance of fires caused by electrical
problems.
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{Danger
Fuses and circuit breakers are
marked with their ampere rating.
Do not exceed the
specified amperage rating when
replacing fuses and circuit
breakers. Use of an oversized
fuse or circuit breaker can result
in a vehicle fire. You and others
could be seriously injured or
killed.
To check a fuse, look at the
silver-colored band inside the fuse.
If the bad is broken or melted,
replace the fuse. Be sure to replace
a bad fuse with a new one of the
identical size and rating.
Fuses of the same amperage can
be temporarily borrowed from
another fuse location, if a fuse goes
out. Replace the fuse as soon as
possible.
Engine Compartment
Fuse Block
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
The engine compartment fuse block
is in the engine compartment, on
the driver side of the vehicle. See
Engine Compartment Overview
0 224
Lift the cover to access the fuse
block.
Caution
Spilling liquid on any electrical
component on the vehicle may
damage it. Always keep the
covers on any electrical
component.
A fuse puller is available inside this
fuse block.
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252 Vehicle Care
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Fuses Usage
F1 Traction control module power
F2 Engine control module power
F3 Air conditioning clutch
F4 –
F5 Engine control module ignition/
Integrated chassis
control module/
Fuel pump power
module
F6 Wipers
F7 Cargo lamp/Bed lighting
F8 Fuel injectors –
even
F9 Fuel injectors –odd
F10 Engine control module 1 Fuses Usage
F11 Oxygen/Mass air flow/Humidity/
Induction air
temperature/
Throttle inlet
pressure sensors
F12 Starter
F13 Traction control module
F14 –
F15 –
F16 –
F17 Front axle actuator
F18 –
F19 Aeroshutters
F20 –
F21 Front blower
F22 Antilock brake system valves
F23 –
F24 Trailer Fuses Usage
F25 Transfer case electronic control
F26 Antilock brake system pump
F27 Trailer brake control module/
Trailer wiring
provisions
F28 Rear window defogger
F29 –
F30 Driver heated seat
F31 –
F32 Passenger heated seat
F33 Right headlamp low beam/Front
right park lamp/
Right front side
marker/Right rear
side marker
F34 Fuel pump power module
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FusesUsage
F35 Integrated chassis control module
F36 Center high-mounted
stoplamp
F37 Right high-beam headlamp
F38 Left high-beam headlamp
F39 –
F40 –
F41 –
F42 –
F43 Not used
F44 –
F45 Vaccuum pump
F46 Engine control module 2 Fuses
Usage
F47 Mid park phase lock/Active fuel
management/
Engine oil and
canister purge
solenoid(s)/Oxygen
sensor
F48 Fog lamps
F49 –
F50 Trailer parking lamps
F51 Horn
F52 –
F53 –
F54 –
F55 –
F56 Washer pump
F57 –
F58 –
F59 –
F60 Mirrors defogger
F61 – Fuses
Usage
F62 Canister vent solenoid
F63 –
F64 Trailer reverse lamp
F65 Left trailer stoplamp/Turn
signal lamps
F66 Right trailer stoplamp/Turn
signal lamps
F67 Electric power steering
F68 –
F69 Battery regulated voltage control
F70 –
F71 –
F72 –
F73 –
F74 Generator
F75 –