2020 CHEVROLET LOW CAB FORWARD engine

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
280 Vehicle Care
Fuse and Relay Location–Cab InteriorFuse locations:
No. Description Rating
1 RR P / WINDOW 25A
2 – –
3 ROOM LAMP, AUDIO 10A
4 DOOR LOCK 15A
5 TRAILER BRAKE 15A
6 P/ WINDOW 25A
7 ABS 10A
8 WIPER 25A
9 H / LAMP LO (LH) 10A
10 LAMPS (BATT) 10A 11 H / LAMP LO (RH) 10A
12 BRAKE LAMPS 10A
13 STARTER 10A
14 H / LAMP HI (LH) 10A
15 H / LAMP HI (RH) 10A
16 MIRROR HEATER 15A

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 281
No. Description Rating17 IGNITION 2 10A
18 IGNITION 1 10A
19 TRANSMISSION 5A
20 ECM 10A
21 METER 10A
22 ECU (BATT) 10A
23 MIRROR 10A
24 AUDIO, ACC 15A
25 HORN 15A
26 TURN, HAZARD 15A
27 TAIL LAMPS 10A
28 ILLUMINATIONS 10A
29 CORNERING LAMPS 10A
30 AIR CONDITIONER 10A
31 – –
32 – –
33 – –
34 – – No. Description Rating
B-1 BACK UP LIGHT 10A
B-2 BACK UP LIGHT (SERVICE) 10A
B-3 AUDIO REVERSE MUTE 10A
B-4 PTO 10A
D-1 CIGAR 20A
D-2 ACCESSORIES SOCKET 15A
D-3 POWER SOURCE 20A
D-4 SPARE 5A

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 283
No. Description19 POWER ACC
20 BLOWER MOTOR Fuse and Relay Location
–Cab Exterior
Fuse and Relay Location
Fuse locations (2): No. Description Rating
1 MARKER LIGHT 20A
2 TAIL MAIN 20A
3 ECM MAIN 15A
4 SCR 20A No. Description Rating
5 PM SENSOR 15A
6 RR DOME LIGHT 15A
7 CONDENSER FAN 20A

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
284 Vehicle Care
No. Description Rating8 A/C 10A
Relay locations (1): No. Description
1 STARTER
2 ECM MAIN
3 NOX & DEF SENSOR
4 A/C COMPRESSOR
5 CONDENSER FAN
6 RR DOME LIGHT
7 SCR HEATER VALVE
8 MARKER LIGHT
9 –
10 –
11 FUEL HEATER When Slow-blow Fuses Blow Out
Slow-blow fuses protect the
electrical circuits, and they are
installed so that they can be quickly
replaced if there is a malfunction.
If an overload exists in the circuit
from the battery, the slow-blow fuse
will blow out before the wiring
harness is damaged to protect the
electrical circuitry. InspectionWhen the headlights and other
devices in the electrical system do
not work, but there is no problem
with the fuses, check the
slow-blow fuse.
The slow-blow fuse is blown if it
looks like the illustration.
Immediately contact the nearest
dealer.

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 285
{Warning
Always use fuses specified by the
dealer when replacing the
slow-blow fuse. Using fuses with
a rating other than that specified,
or using wire or tin foil, etc., could
result in fire or damage.
If the new fuses blow right away
and the cause is unknown,
contact your dealer.
Do not inspect or replace fuses
when the starter switch is in the
ON position. Doing so may lead
to an accident.(Continued)
Warning (Continued)
When inspecting fuses, be sure to
park the vehicle on flat, level
ground and apply chocks to the
wheels.
It is not necessary to open or close
the cover unless trouble is found.
The relay box structure makes it
difficult for water to enter. If you
should spill water or a beverage of
the cover, however, wipe it off
before opening the cover.
The area around the cover will get
warm when the vehicle is being
driven, but this is not abnormal.
Wheels and Tires
The operating load and cold inflation
pressure on the rim and wheel must
not exceed the rim and wheel
manufacturer's recommendations
even though the tire may be
approved for a higher load or
inflation. Rim and wheel may be
identified (stamped) with maximum
load and maximum cold inflation
rating. For rims and wheels not so
identified or for service conditions
exceeding the rate capacities,
consult the rim and wheel
manufacturer to determine rim and
wheel capacities for the intended
service. The factory-installed tires
on this vehicle were selected to
provide the best all-around tire
performance for normal operation.
When inflated, as shown on the
vehicle, they have the load carrying
capacity to operate satisfactorily at
all loads up to and including the full
rated load specified for the vehicle.
For more information concerning the
differences in capacities of tires and

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
286 Vehicle Care
rims, refer to the“Tire and Rim
Association Inc. Yearbook”, or your
tire dealer.
Tire Inflation
{Warning
To reduce the risk of loss of
vehicle control and personal
injury:
Tires must be properly inflated,
and your vehicle must not be
overloaded (see the information
on Information on Loading the
Vehicle 046 and "Tire Load and
Inflation Table" under Tire
Pressure 0297).
Be sure to keep tires properly
inflated. A tire that is run while
seriously underinflated may
overheat to the point where the
tire may lose air suddenly and/or
catch fire, possibly resulting in
personal injury and/or property
damage. See
“Tire Load and Inflation Table”
under Tire Pressure 0297.
In no case should the front or rear
tire load exceed the maximum
recommended gross axle weight
rating (front GAWR or rear GAWR).
The efficiency of the vehicle will be
upset if air pressure in the tires are
not equal. Balanced inflation results
when the tires on the same axle
carry the same air pressure.
A difference in pressure between
the front and rear tires may be
permissible within certain limitations,
however, there should not be a
difference in pressures between the
right and left tires on the same axle.
Always use a truck tire pressure
gauge (a pocket-type gauge is not
advised) when checking inflation
pressures. Visual inspection of tires
for inflation pressures is not enough,
especially in the case of radial tires.
Underinflated radial tires may look
similar to correctly inflated radial
tires. If the inflation pressure on a
tire is found to be low frequently,
have your dealer correct the cause. Be sure to install the tire inflation
valve caps to prevent dirt and
moisture from getting into the valve
core, which could cause air leakage.
An underinflated tire in a dual wheel
assembly is harder to notice than
one in a single wheel assembly. The
properly inflated dual tire carries its
own load plus that of the
underinflated tire. Both tires can
overheat, which may result in
property damage and/or personal
injury (see previous WARNING).
Tires Used or Stored for a Long
Period of Time
Tires are a rubber product and
degrade over time, even if they are
not being used. If any of your tires is
5 to 7 years old or more, please
have them inspected for safe
driving. For further information,
please check with the tire
manufacturer.
Dual Tire Operation
The outer tire of a pair on dual
wheel installations generally wears
faster than the inner tire. If this

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 287
occurs, reverse the position of the
tires to equalize wear and get better
tire life.
In addition, when trucks are driven
continuously on high-crown roads,
an increase in air pressure of
35 kPa (5 psi) in the outer tire of a
dual tire operation will prolong outer
tire life. Be sure not to exceed the
inflation pressure limits shown on
the“VIN, Weight Rating, and
Greenhouse Gas (GHG) Emissions
Plate.” SeeVehicle Identification
Number (VIN) 0343.
Wheel and Tire Balancing
Proper tire balancing provides the
best riding comfort and helps to
reduce tire tread wear.
Out-of-balance tires can cause
annoying vehicle vibration and
uneven tire wear, such as cupping
and flat spots. See your authorized
dealer for wheel balancing.
Front End Alignment
Proper front end alignment improves
tire tread mileage. Your vehicle's
front end suspension parts should
be inspected often and aligned when needed. (See the
Maintenance Schedule for more
information.) Improper alignment will
not cause the vehicle to vibrate;
however, improper toe-in alignment
will cause front tires to roll at an
angle that will result in faster tire
wear. Incorrect caster or camber
alignment will cause your front tires
to wear unevenly, and may cause
the vehicle to "pull" to the left or
right.
Tire Traction
A decrease in driving, cornering and
braking traction occurs when water,
snow, ice, gravel or other material is
on the road surface. Driving
practices and vehicle speed should
be adjusted to the road conditions.
When driving on wet or slushy
roads, it is possible for a wedge of
water to build up between the tire
and road surface. This is known as
hydroplaning, and may cause partial
or complete loss of traction, vehicle
control and stopping ability; this
condition is also more likely with
worn tires.
To reduce the chance of traction
loss, follow these tips:
.
Slow down during rainstorms or
when roads are slushy.
. Slow down if the road has
standing water or puddles.
. Replace tires when front tread
depth is 3.2 mm (4/32 in.) and
rear tread depth is 1.6 mm
(2/32 in.).
. Keep tires properly inflated.
Tire Replacement
Recommendations
{Warning
Do not mix different construction
types of tires on your vehicle such
as radial, bias and bias-belted
tires except in emergencies,
because vehicle handling could
be affected and may result in loss
of vehicle control, or personal
injury or death. (Continued)