engine CHEVROLET LOW CAB FORWARD 2020 Owner's 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
270 Vehicle Care
Headlamps and Front
Turn Signal
Replacing the Headlamps
When the bulb has blown out,
replace it with a bulb of the
specified wattage. Be careful not to
excessively tighten the mounting
screws when replacing the
headlamp bulbs.
Do not replace a bulb with other
than the specified wattage.
Proper aiming of the headlamps is
important to ensure sufficient
illumination of the highway without
blinding other motorists. When
replacing headlamp bulbs, have the
headlamp aim adjusted at your
dealer.
When replacing a bulb, make sure
the light switch is“OFF”.
See Bulb Replacement 0267.
1. Remove the front grille (3).
Remove the screw (4) from the
center of the grille. Push up on
the tabs of the five clips (1) on
the upper side of the grille and
pull the grille toward you to
remove it. Loosen the nuts (2)
for the turn signal light.2. Remove the turn signal lamp.Open the front door. Use a
phillips head screwdriver to
remove the two screws
between the door and the cab.

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 271
3. Tilt the turn signal lamp unitdown toward the front of the
vehicle and remove it.
4. Disconnect the connector (1)for the turn signal lamp from
the socket (2) and then remove
the lamp.
6. Disengage the rubber seals (2)
from the two projections (3) at
the bottom of the headlamp.
Remove the four bolts (1).
7. Disconnect the headlampconnector (5) and the parking
lamp socket (3). Remove the
headlamp assembly.
When removing the headlamp
connector, pull out the
connector while holding the
center portion of the rubber
boot. Otherwise, the headlamp
bulb will be broken.

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
272 Vehicle Care
8. Remove the rubber boot (2).Push the right side of the
clip (1) that holds the bulb (3)
in place and slide it upwards to
disengage the clip.9. Remove the bulb (1) from thesocket (2) and replace with a
new one.
10. After replacing the bulb, reverse steps 1-8 to install.
Do not touch the glass of the bulb
with your hand. Soiling the glass will
cause the bulb to blow out.
When attaching the rubber boot,
press in both the outside and inside
circumference of it. Make sure that
the rubber boot, the headlamp
assembly, and the bulb are securely
installed without any raised section. If the rubber boot is not firmly in
place, water could get inside the
headlamp and lead to a breakdown.
Replacing Parking Lamps
1. Refer to
“Replacing the
Headlamps” and remove the
headlamp assembly.
2. Pull the bulb out from the parking lamp socket and
replace with a new one.

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 273
3. To install the lamps, performthe same sequence of
operations in reverse, taking
care to turn the connector
clockwise to lock it securely.
If the socket is not locked securely,
water could get inside the lamp and
lead to a breakdown.
Replacing a Front Turn
Signal Lamp
Do not replace a bulb with other
than the specified wattage. This will
cause abnormal flashing,
particularly for turn signal lamps.
When replacing a bulb, make sure
the light switch is OFF.
1. While referring to “Replacing
the Headlights”, tilt the turn
signal lamp assembly down
toward the front of the vehicle
and remove it.
2. Disconnect the connector for the turn signal light and then
remove the socket.

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
274 Vehicle Care
3. Pull the bulb from the socketand replace it with a new one.
4. To install the lamps, perform the same sequence of
operations in reverse, taking
care to turn the connector
clockwise to lock it securely.
If the socket is not locked securely,
water could get inside the light and
lead to a breakdown.
Roofmarker Lamps
1. Loosen the screws (2) and remove the lens (1). 2. Remove the bulb (3) from the
socket (4) and replace it with a
new one.
3. To install the lights, follow the removal procedure in reverse.
If the screwing procedure is
inadequate, water may infiltrate into
the lamp unit.
Sidemarker Lamps
(Including Turn Signal
and Cornering Lamps)
Do not replace a bulb with other
than the specified wattage. This will
cause abnormal flashing,
particularly for turn signal lamps.
When replacing a bulb, make sure
the light switch is "OFF".
1. Open the front door, remove the rubber cap (1) in the lower
part of the door, and loosen
the nut (2).

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 275
2. Slide the cornering lamp (3)and the side turn signal lamp
forward relative to the vehicle.
Disconnect the clip (1) on the
lamp’s rear side from the door
panel (2) and pull out the lamp.
If you pull out the light rear
section by too much when
removing the clip on the rear
side, the clip on the lamp front
side may be damaged.
3. When the clip (1) has been
removed, pull the lamp out
while sliding it out toward the
rear of the vehicle. 4. Loosen the socket by turning it
counterclockwise.
5. Pull the bulb out from thesocket and replace it with a
new one.
6. To install the lights, perform the same sequence of operations
in reverse taking care of the
following points:
A. Turn the socket clockwiseto lock securely.
If the socket is not locked
securely, water could get
inside the light and lead to
a breakdown.
B. Insert the clip on the backof the rear part of the light
into the door panel.
C. Push the front part of the light into the door panel,
and insert the clip on the
back of the front part of the
light in the door panel.

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
276 Vehicle Care
D. Open the front door, tightenthe nut from the inside of
the door, and install the
rubber cap.
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps
1. Turn Signal Lamp
2. Taillamp/Stoplamp
3. Back-Up Lamp
4. Lens
1. Loosen the screws and remove the lens.
2. Loosen the bulb by turning it counterclockwise while
pressing on it.
3. To install the lights, follow the removal procedure in reverse.
License Plate Lamp
1. Bulb
2. Lens
3. Screw
4. Cover
1. Loosen the screws and removethe cover.
2. Remove the lens.
3. Loosen the bulb by turning it counterclockwise while
pressing on it.
4. To install the lights, follow the removal procedure in reverse.

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 277
Interior Lamps
1. Remove the lens and pull outthe bulb.
2. To install the lights, follow the removal procedure in reverse.
Electrical System
Electrical System
Overload
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.
Replacing the Fuses and Relays
Your vehicle is equipped with fuses
and fusible links to protect your
electrical wiring and equipment in
case of electrical overload.
When the lights do not come on or
flash, or the equipment in the
electrical system does not operate,
check to see if a fuse has blown. Fuses :
In case of an electrical
overload, the fuse will blow and stop
the flow of current in the circuit
before electrical components
become damaged.
The cause of the circuit overload
must be identified and corrected
before the blown fuse is replaced,
or else the new fuse will also blow.
Since different circuits handle
different amounts of current, fuses
of various ampere ratings are used.
Be sure to replace a blown fuse with
a fuse of the correct rating.
To know if a fuse is blown or not,
remove the suspected fuse and look
at the wire for a break. If the wire is
broken, replace the fuse with one of
equal amperage rating.
The amperage rating of each fuse is
molded in its head.
Fuses are installed in the fuse
panel.

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
278 Vehicle Care
The Location of Fuses and Relays
The fuses (3) and relays (2) are
located in the lower part of the
instrument panel in the center and
in the left rear of the cab.
The cover (1) must be opened in
order to carry out inspection and
replacement. In addition, the
cover (1) of the relay box at the left
rear of the cab must also be opened
at this time.
If you should spill water or a
beverage on the cover, wipe it off
before opening the cover.
The area around the cover may get
warm when the vehicle is being
driven, but this is not abnormal.Replacing Fuses
1. Before replacing fuses, firmly apply the parking brake, move
the selector lever to the
P (Park) position, and turn the
engine control switch to the
LOCK position.
2. The fuse puller is stored in the fuse box inside the cab. Place
the fuse puller on the fuse and
pull it out.
3. If the fuse appears asshown (2), the fuse is blown.
Replace with a spare fuse (1).
Spare fuses are stored in the
fuse box inside the cab.

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 279
{Warning
Always use fuses specified for the
vehicle. 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.
When inspecting fuses, be sure to
park the vehicle on flat, level
ground and apply chocks to the
wheels.
Replacing Relays
Before replacing the relays, contact
the nearest dealer.
The vehicle may not be equipped
with all of the fuses, relays, and
features shown. 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.