brake light CHEVROLET LOW CAB FORWARD 2020 Service Manual

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
224 Driving and Operating
Running Out of Fuel
When the Fuel Tank is Empty
When the fuel tank is empty, air will
enter the fuel system, so refueling
alone will not be enough to restart
the engine. Use the following
methods to bleed the fuel system.
Bleeding the Fuel System
Steps for Refueling1. Follow the directions in "Parking Brake Lever" under
Parking Brake 0211. 2. Select the correct fuel (See
"Diesel Fuel Requirement and
Fuel System"). Follow any
posted safety rules. Stand to
the side, never above or
opposite the filler opening.
3. Check that the fuel cap is tight, and see to it that engine oil,
engine coolant in the reservoir,
and washer fluid, etc. are at
proper levels. Then do the
Driver Daily Checklist.
See Owner Checks and Services
0 330.
Driving your vehicle until the fuel
tank is empty may activate the
check engine malfunction indicator
light. You do not need to have your
vehicle checked. After refueling,
perform the following:
. Bleed the fuel system.
. Start, turn off and restart the
engine three or four times.
. The check engine malfunction
indicator light will be cancelled. Before Starting the Engine
1. The priming pump (1) is
located on the outboard side of
the left frame rail, in front of the
batteries. Place a container
beneath the air bleed plug (2)
to receive fuel, and then fully
loosen the plug.
2. Attach a clear hose onto the air bleed plug, direct the clear
hose into a catch pan.
3. Pump the priming pump (1) up/ down for 65 times to get most
of the air bubbles out. Note fuel
was drawn into the filter bowl at
around 40 - 50 times.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
254 Vehicle Care
Follow the recommendations for
brake checks in the Maintenance
Schedule.
GM replacement brake lining
material is recommended for this
vehicle to maintain the balance
between front and rear brake
performance. GM replacement
brake parts have been carefully
selected to provide the proper brake
balance for purposes of both
stopping distance and controllability
over the full range of operating
conditions. Installation of front or
rear brake lining material with
performance different from that of
the replacement parts
recommended for this vehicle can
change the intended brake balance
of this vehicle.
Checking the Brake Electric
Vacuum Pump (4500HD/
4500XD Series)
1. Turn the engine control switchto the "ON" position (do not
start the engine), and press the
brake pedal several times. 2. Check for the noisy sound of
the electric vacuum pump
inside the instrument panel at
the same time as vacuum
warning buzzer sound, and
check that the brake low
vacuum warning light
comes on.
3. Then, start the engine. The main vacuum pump driven by
the engine will start running.
If the electric vacuum pump
operation (noisy sound) and
the vacuum warning buzzer
stop, and the brake low
vacuum warning light goes off
thereafter, the operation is
normal.
4. If you cannot hear the noisy sound or the noisy sound stays
on all the time, have the
vehicle inspected by the
nearest dealer immediately.Hydraulic Brake Booster (HBB)
The 5500HD, 5500XD models are
equipped with an HBB system. HBB
is a brake booster device that utilizes hydraulic pressure from the
HBB pump integral with the power
steering pump.
If the brake booster warning light
comes on or a warning buzzer
continues to sound, there may be a
problem with the HBB.
If this warning light comes on while
driving, immediately stop your
vehicle at a safe place well clear of
traffic and promptly contact the
nearest dealer for inspection.
Hydraulic brake booster (HBB)
characteristics
In the 5500HD, 5500XD models, an
unusual sound from under the
instrument panel may be heard from
the hydraulic system while brakes
are used. It does not mean trouble.
It is not a sign of malfunction.
If you pump the brakes with the
engine off, a squeaking sound can
be heard. This comes from the
auxiliary accumulator. It is not a
malfunction. With the engine
running, a similar sound can be
heard during sudden braking.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
256 Vehicle Care
lead to dragging brakes or other
major brake problems. As such,
mixing of these two fluids can
ultimately lead to vehicle fire or
other serious crashes.
When the pump operates while the
engine is running, the fluid in the
hydro-booster will become hot.
During normal braking, the
temperature in piping and within the
hydro-booster can rise above
100 °C (212 °F). For this reason,
special care will be required when
working with hydro-booster
components. If the hydro-booster is
to be removed from the vehicle,
shut off the engine and then allow at
least 30 minutes for it to cool down
before beginning this operation.
Even when the engine is stopped,
the hydro-booster's accumulator will
remain in a highly-pressurized
condition for a significant period of
time. Before removing the
hydro-booster or piping from the
vehicle, stop the engine and press
the brake pedal at least 10 times in
order to lower the accumulator
pressure to atmospheric pressure.This is of particular importance
when removing components such
as the accumulator or pressure
switch from the hydro-booster.
If these operations are attempted
while the accumulator is still at a
high pressure, hydro-booster fluid
may spray out.
Checking the Hydro-booster Fluid
Level
Check the hydro-booster fluid level
and change the fluid according to
the Maintenance Schedule.
The hydro-booster fluid level is
correct if it is between the "MAX"
and "MIN" lines. If the level is too
low, add fluid up to the "MAX" line.
Be sure to use Dexron VI ATF fluid
when adding fluid. The brake
booster reservoir is located behind
the cab on the left side.
Brake Pedal
Stroke
Shut off the engine and press the
brake pedal about 10 times strongly,
then check the brake pedal for free
play by lightly pushing it by hand
until you feel resistance.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
282 Vehicle Care
Relay LocationRelay locations:
No. Description
1 STOP LAMP
2 DAYTIME RUNNING LAMP
3 KEY ON
4 PARKING/NEUTRAL
5 –
6 WIPER MAIN
7 HORN
8 WIPER HI LO
9 TRAILER BRAKE
10 POWER WINDOW
11 BACK UP LAMP
12 POWER WINDOW
13 HEAD LAMP LO
14 VACUUM PUMP
15 HEAD LAMP HI
16 TAIL LAMP
17 CIGAR LIGHTER
18 CORNERING LAMP

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Vehicle Care 289
Recommended replacement tire for Greenhouse Gas (GHG) emissions
Tire sizeTire makerTire name Rolling
resistance
LT215/85R16E BRIDGESTONE CORPORATION
M779AZ LRRA
THE YOKOHAMA RUBBER CO., LTD. TY213B LRRA
225/70R19.5F BRIDGESTONE CORPORATION
M895Z LRRA
SUMITOMO RUBBER INDUSTRIES, LTD. (DUNLOP) SP688 LRRA
If the original equipment tires are
low rolling tires, it is recommended
to use the LRRA tires shown in the
above table.
Refer to the emission control
identifiers on Greenhouse Gas
(GHG) emission plate for your
original equipment tires. Also,
please refer to “VIN, Weight Rating,
and Greenhouse Gas (GHG)
Emissions Plate” for the location of
the Greenhouse Gas (GHG)
emission plate. See Vehicle
Identification Number (VIN) 0343. Wheel Replacement
Recommendations
Wheels must be replaced if they
become damaged (for example:
bent, heavily rusted, leak air) or if
wheel nuts often become loose. Do
not use bent wheels that have been
straightened and do not use inner
tubes in leaking wheels which are
designed for tubeless tires. Such
wheels may have structural damage
and could fail without warning.
When replacing wheels for any
reason, the new wheels should be
equal in load capacity, diameter, width, offset and mounting types to
those originally installed in your
vehicle.
A wheel of the wrong size or type
may adversely affect wheel and
bearing life, brake cooling,
speedometer/odometer calibration,
stopping ability, headlight aim,
bumper height, vehicle ground
clearance and tire or tire chain
clearance on the body and chassis.
Replacement with "used" wheels is
not advised. They may have been
subjected to harsh treatment or very
high mileage and could fail without
warning.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Vehicle Care 303
the negative (–) terminal which
is grounded (attached to the
engine block, or frame rail).
2. Position the vehicle with the good (charged) battery so that
the booster (jumper) cables will
reach. But never let the
vehicles touch. Also, be sure
the booster cables to be used
do not have loose or missing
insulation.
3. In both vehicles, turn off the ignition (engine control) switch
and all lights and accessories
except the hazard flasher or
any lights needed for the work
area. In both vehicles, apply
the parking brake firmly and
move the selector lever to the
"P" position.
4. Unlatch the latches (1) and
remove the battery cover (2)
and connect the jumper cables
in the numbered sequence in
the drawing below. Make sure
the cable clamps do not touch
any other metal parts. Make sure the cables are not
on or near pulleys, fans or
other parts that will move when
the engine is started.
When it is difficult to start the
engine in a cold area, first start
the engine of the vehicle with
the booster battery or batteries
and a few minutes after that
start the engine of the disabled
vehicle.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
330 Service and Maintenance
Owner Checks and
Services
Before Driving
Proper care and driving is important
not only for extended service life of
your vehicle, but also for improved
fuel and oil economy. Drive carefully
and defensively. Be sure you know
how to use your truck and its
equipment before operating it.
Starting and Operating
Proper care and operation will not
only extend the service life of your
vehicle but also improve fuel
economy.
Check Around the Vehicle Before
Starting the Engine
Before pulling away, perform a
thorough safety check, making sure
there are no children or obstructions
around the vehicle.
Take off the chocks after confirming
that the parking brake is securely
applied. Sit behind the wheel, adjust
the seat position, and buckle up theseat belt. The passengers are also
required to buckle up the seat belts.
Adjust the positions of the steering
wheel and mirrors. Lock the doors.
Turn the power of the dome light or
accessories OFF before starting the
engine.
Engine Conditions
Checking the Engine for
Startability and Abnormal Noises
1. Make sure the parking brake is securely engaged. Step firmly
on the brake pedal.
2. Make sure the selector lever is in "P" or "N" position.
For safety, firmly press the
brake pedal before starting the
engine.
3. Turn the engine control switch to start the engine.
Check that the engine starts
quickly with no abnormal
noises. Checking Condition of the Engine
at Low Speeds and during
Acceleration
1. Make sure the transmission is in the "P" or "N" position and
the parking brake is securely
engaged.
2. Turn the engine control switch to start the engine, and run it to
warm up.
3. Check that the engine is running at a speed within the
standard idle speed range.
During regeneration of the
diesel particulate filter (DPF),
the engine idle speed may
increase.
4. Drive the vehicle, making sure the accelerator pedal does not
stick when gradually
accelerating, the engine speed
rises smoothly and it does not
knock.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Service and Maintenance 331
Recommended Daily
(Pre-operation) Inspections
These checks are in addition to, not
instead of, any legally required daily
inspections. See related topics
under "Maintenance Schedule",
especially if problems are found.
For safe and comfortable driving,
keep record of the distances driven
and the condition of the vehicle
during operation. Perform
inspections at appropriate intervals,
and perform maintenance in
accordance with the findings of the
inspections. If an inspection reveals
an abnormality or there was an
abnormality the previous time the
vehicle was driven, have the vehicle
repaired by the nearest dealer
before it is driven again.1. Components that showed abnormalities during the
previous operation
.Check components that
showed abnormalities
during the previous
operation 2. Checks performed at the
engine
.Fan belt looseness and
damage
. Engine oil level
. Engine coolant level
. Power steering fluid level
3. Checks performed from the driver's seat
.Brake fluid level
. Brake pedal free play
. Operation of meters,
gauges and warning/
indicator lights
. Engine startability,
abnormal noise and color of
exhaust gases
. Parking brake lever stroke
. Windshield washer fluid
spray condition and
windshield wiper
effectiveness
. Windshield washer fluid
level .
Steering wheel position and
free play
. Operation of horn and turn
signal lights
. Door lock operation
4. Checks performed during a walk around the vehicle
.Illumination, flashing,
contamination, damage and
obstruction of lights
. Contamination, damage ad
obstruction of windows,
mirrors and reflectors
. Leaf spring damage
. Oil, engine coolant, fuel,
brake fluid and power
steering fluid leaks
. Water separator
5. Checking wheels and tires .Air pressure
. Cracks and other damage
. Abnormal wear
. Tread depth

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
332 Service and Maintenance
.Mounting condition of all
wheel nuts
6. Checks performed after the engine startup
.Oil, engine coolant, fuel,
brake fluid and power
steering fluid leaks
. Inspect the exhaust system,
checking that the tailpipe is
clear
7. Checks performed while driving the vehicle
.Brake effectiveness
. Engine abnormal noises
Keep the Floor Around the Driver
Seat Clean and Tidy
{Warning
It is extremely dangerous to have
empty cans, empty bottles,
or other items rolling around on
the floor because they could get
trapped under the brake pedal
and prevent brake application. (Continued)
Warning (Continued)
For proper pedal operation, it is
also essential to lay floor mats
properly. Incorrectly installed floor
mats would hinder free movement
of the pedals.
Do not use the dashboard pocket
or the top of the dashboard as a
place to put items that could roll,
which could interfere with your
driving. You and others could be
seriously injured.
Choose Your Footwear Suitable
for Driving
{Warning
Choose footwear that ensures
proper operation of pedals when
driving the vehicle. Use of
footwear unsuitable for driving
may cause an accident. The
driver could be seriously injured
when not wearing the proper
footwear.
Electrical System
Following the after-delivery service,
it is the owner's responsibility to
check all wiring periodically for
cracked, chafed or oil-soaked
insulation and maintain it in a clean
and tight condition to ensure
satisfactory operation of the
electrical system.
Headlights and Turn Signal
Lights
Turn the engine control switch to the
"ON" position, and then check the
way in which the headlights, turn
signal lights, and other exterior
lights come on and flash. In
addition, press the brake pedal to
confirm whether the stop lights
come on, and shift the transmission
to "R" position to confirm whether
the back up lights come on. Also
examine the lights for discoloration,
damage, and looseness.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
336 Service and Maintenance
Additional
Maintenance and Care
Owner Safety and Routine
Maintenance
Listed below are vehicle checks
which should be made periodically
by either the owner or a qualified
technician to ensure proper
performance and safety of your
vehicle. Take any problems promptly
to a technician for service advice.
For your safety and that of others,
any of the safety-related
components that may have been
damaged in a crash should be
checked and necessary repairs
performed before operating your
vehicle.
At the minimum, these routine
checks should be made every
6 months or 16,000 km
(10,000 miles), whichever comes
first. Whenever repairs are
necessary, have them completed
before operating the vehicle.A: Parking Brake :
Park on a fairly
steep hill and hold the vehicle with
the parking brake only. This checks
holding ability.
Before checking item (B) below, be
sure to have enough room around
the vehicle. Then firmly apply both
the parking brake see Parking
Brake 0211 and the regular brakes.
Do not use the accelerator pedal.
If the engine starts, be ready to turn
off the engine control switch at
once. Take these precautions
because the vehicle could move
without warning and possibly cause
injury or property damage.
B: Starter Safety Switch : Check
by trying to start the engine in each
gear. The starter should crank only
at selector position "P" or "N".
C: Transmission Shift Indicator :
Check that the indicator points to
the gear chosen.
D: Steering : Be alert for any
changes in steering action. An
inspection or service is needed
when: the steering wheel is harder to turn or has too much free play,
or when there are strange sounds
when turning or parking.
E: Wheel Alignment, Balance, and
Tires :
Check tires for abnormal
wear or damage. Also, check for
damaged wheels. A pull right or left
on a straight and level road may
show the need for a wheel
alignment. A vibration of the
steering wheel or seat at normal
highway speeds may mean a wheel
balancing is needed. Check tire
pressure when the tires are "cold,"
at least monthly, and whenever the
vehicle is serviced.
Check the pressure more often if
daily checks show it's needed.
(Refer to "Recommended Daily
(Pre-operation) Inspections" under
Owner Checks and Services 0330).
Change tire pressure as needed
when changing loads.
F: Brakes : Be alert to illumination
of the brake system warning light or
brake low vacuum warning light
(4500HD, 4500XD models) or the
tone alarm, or changes in braking
action, such as repeated pulling to