2021 RAM 1500 wiring

88GETTING TO KNOW YOUR VEHICLE
6. Disconnect the wiring harness by pushing
on the two release tabs, ensuring the
connector bracket does not fall into the sill.

Connected Wiring Harness
Disconnected Body Side Harness
7. Connect the body side plug (provided in the
glove compartment) to the body side wiring
harness and insert the bracket back into
the sill.

Body Side Plug (One Piece)

8. Connect the tailgate plugs (provided in the glove compartment) to the tailgate wiring
harness to ensure that the terminals do not
corrode.
Tailgate Plugs (Two Pieces)

9. Tape the tailgate harness and bracket against the forward-facing surface of the
tailgate. This will prevent damaging the
connector and bracket when storing or
reinstalling the tailgate.
1 — First Release Tab
2 — Second Release Tab
1 — Large Plug
2 — Small Plug

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STARTING AND OPERATING223
Integrated Trailer Brake Module — If
Equipped
Your vehicle may have an Integrated Trailer
Brake Module (ITBM) for Electric and Electric
Over Hydraulic (EOH) trailer brakes.
NOTE:
This module has been designed and verified
with electric trailer brakes and new EOH
systems. Some previous EOH systems may not
be compatible with ITBM.

Integrated Trailer Brake Module (ITBM)
The user interface consists of the following:
GAIN Adjustment Buttons (+/-)
Pushing these buttons will adjust the brake
control power output to the trailer brakes in
0.5 increments. The GAIN setting can be
increased to a maximum of 10 or decreased to
a minimum of 0 (no trailer braking).
GAIN
The GAIN setting is used to set the trailer brake
control for the specific towing condition and
should be changed as towing conditions
change. Changes to towing conditions include
trailer load, vehicle load, road conditions and
weather.
Manual Brake Control Lever
Slide the manual brake control lever to the left
to activate power to the trailer's electric brakes
independent of the tow vehicle's brakes. If the
manual brake control lever is activated while
the brake is also applied, the greater of the two
inputs determines the power sent to the trailer
brakes. The trailer and the vehicle’s stop lamps will
come on when braking normally with the vehicle
brake pedal. Only the trailer stop lamps will
come on when the manual brake control lever is
applied.
Trailer Brake Status Indicator Light
This light indicates the trailer electrical
connection status.
If no electrical connection is detected after the
ignition is turned on, pushing the GAIN
adjustment button or sliding the manual brake
control lever will display the GAIN setting for
10 seconds and the “Trailer Brake Status
Indicator Light” will not be displayed.
If a fault is detected in the trailer wiring or the
Integrated Trailer Brake Module (ITBM), the
“Trailer Brake Status Indicator Light” will flash.
1 — GAIN (-) Adjustment Button
2 — GAIN (+) Adjustment Button
3 — Manual Brake Control Lever
4

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STARTING AND OPERATING225
Display Messages
The trailer brake control interacts with the
instrument cluster display. Display messages,
along with a single chime, will be displayed
when a malfunction is determined in the trailer
connection, trailer brake control, or on the
trailer Úpage 114. NOTE:
An aftermarket controller may be available
for use with trailers with air or elec
-
tric-over-hydraulic trailer brake systems. To
determine the type of brakes on your trailer
and the availability of controllers, check with
your trailer manufacturer or dealer.
Removal of the ITBM will cause errors and it
may cause damage to the electrical system
and electronic modules of the vehicle. See
your authorized dealer if an aftermarket
module is to be installed.
Towing Requirements — Trailer Lights And
Wiring
Whenever you pull a trailer, regardless of the
trailer size, stoplights and turn signals on the
trailer are required for motoring safety.
The Trailer Tow Package may include a four-pin
and seven-pin wiring harness. Use a factory
approved trailer harness and connector.
NOTE:
Do not cut or splice wiring into the vehicle’s
wiring harness. The electrical connections are all complete to
the vehicle but you must connect the harness to
a trailer connector. Refer to the following
illustrations.
NOTE:
Disconnect trailer wiring connector from the
vehicle before launching a boat (or any other
device plugged into vehicle’s electrical
connect) into water.
Be sure to reconnect once clear from water
area.

Four-Pin Connector

WARNING!
Connecting a trailer that is not compatible
with the ITBM system may result in reduced
or complete loss of trailer braking. There may
be a increase in stopping distance or trailer
instability which could result in personal
injury.
CAUTION!
Connecting a trailer that is not compatible
with the ITBM system may result in reduced
or complete loss of trailer braking. There may
be a increase in stopping distance or trailer
instability which could result in damage to
your vehicle, trailer, or other property.
1 — Ground
2 — Park
3 — Left Stop/Turn
4 — Right Stop/Turn
4

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342SAFETY
SUPPLEMENTAL RESTRAINT SYSTEMS
(SRS)
Some of the safety features described in this
section may be standard equipment on some
models, or may be optional equipment on
others. If you are not sure, ask an authorized
dealer.
The air bag system must be ready to protect you
in a collision. The Occupant Restraint Controller
(ORC) monitors the internal circuits and
interconnecting wiring associated with the
electrical Air Bag System Components. Your
vehicle may be equipped with the following Air
Bag System Components:
Air Bag System Components
Occupant Restraint Controller (ORC)
Air Bag Warning Light
Steering Wheel and Column
Instrument Panel
Knee Impact Bolsters
Driver and Front Passenger Air Bags
Seat Belt Buckle Switch
Supplemental Side Air Bags
Front and Side Impact Sensors
Seat Belt Pretensioners
Seat Track Position Sensors
Occupant Classification System
Air Bag Warning Light
The Occupant Restraint Controller
(ORC) monitors the readiness of the
electronic parts of the air bag system
whenever the ignition switch is in the
START or ON/RUN position. If the ignition switch
is in the OFF position or in the ACC position, the
air bag system is not on and the air bags will not
inflate. The ORC contains a backup power supply
system that may deploy the air bag system even
if the battery loses power or it becomes
disconnected prior to deployment.
The ORC turns on the Air Bag Warning Light in
the instrument panel for approximately four to
eight seconds for a self-check when the ignition
switch is first in the ON/RUN position. After the
self-check, the Air Bag Warning Light will turn
off. If the ORC detects a malfunction in any part
of the system, it turns on the Air Bag Warning
Light, either momentarily or continuously. A
single chime will sound to alert you if the light
comes on again after initial startup.
The ORC also includes diagnostics that will
illuminate the instrument panel Air Bag Warning
Light if a malfunction is detected that could
affect the air bag system. The diagnostics also
record the nature of the malfunction. While the
air bag system is designed to be maintenance
free, if any of the following occurs, have an
authorized dealer service the air bag system
immediately.
Failure to replace the seat belt assembly
could increase the risk of injury in colli
-
sions.
Do not use the Automatic Locking Mode to
restrain occupants who are wearing the
seat belt or children who are using booster
seats. The locked mode is only used to
install rear-facing or forward-facing child
restraints that have a harness for
restraining the child.
WARNING! (Continued)

21_DT_OM_EN_USC_t.book Page 342

352SAFETY
Rollover Events
Side Air Bags and seat belt pretensioners are
designed to activate in certain rollover events.
The Occupant Restraint Controller (ORC)
determines whether deployment in a particular
rollover event is appropriate, based on the
severity and type of collision. Vehicle damage by
itself is not a good indicator of whether or not
Side Air Bags and seat belt pretensioners
should have deployed.
The Side Air Bags and seat belt pretensioners
will not deploy in all rollover events. The rollover
sensing system determines if a rollover event
may be in progress and whether deployment is
appropriate. In the event the vehicle
experiences a rollover or near rollover event,
and deployment is appropriate, the rollover
sensing system will deploy the side air bags and
seat belt pretensioners on both sides of the
vehicle.
The SABICs may help reduce the risk of partial
or complete ejection of vehicle occupants
through side windows in certain rollover or side
impact events.Air Bag System Components
NOTE:
The Occupant Restraint Controller (ORC) moni -
tors the internal circuits and interconnecting
wiring associated with electrical Air Bag System
Components listed below:
Occupant Restraint Controller (ORC)
Air Bag Warning Light
Steering Wheel and Column
Instrument Panel
Knee Impact Bolsters
Driver and Front Passenger Air Bags
Seat Belt Buckle Switch
Supplemental Side Air Bags
Front and Side Impact Sensors
Seat Belt Pretensioners
Seat Track Position Sensors
Occupant Classification System
If A Deployment Occurs
The front air bags are designed to deflate
immediately after deployment.
NOTE:
Front and/or side air bags will not deploy in all
collisions. This does not mean something is
wrong with the air bag system.
If you do have a collision which deploys the air
bags, any or all of the following may occur:
The air bag material may sometimes cause
abrasions and/or skin reddening to the occu -
pants as the air bags deploy and unfold. The
abrasions are similar to friction rope burns or
those you might get sliding along a carpet or
gymnasium floor. They are not caused by
contact with chemicals. They are not perma -
nent and normally heal quickly. However, if
you haven’t healed significantly within a few
days, or if you have any blistering, see your
doctor immediately.
As the air bags deflate, you may see some
smoke-like particles. The particles are a
normal by-product of the process that gener -
ates the non-toxic gas used for air bag infla -
tion. These airborne particles may irritate the
skin, eyes, nose, or throat. If you have skin or

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354SAFETY
(Continued)
Enhanced Accident Response System
Reset Procedure
In order to reset the Enhanced Accident
Response System functions after an event, the
ignition switch must be changed from ignition
START or ON/RUN to ignition OFF. Carefully
check the vehicle for fuel leaks in the engine
compartment and on the ground near the
engine compartment and fuel tank before
resetting the system and starting the engine.
After an accident, if the vehicle will not start
after performing the reset procedure, the
vehicle must be towed to an authorized dealer
to be inspected and to have the Enhanced
Accident Response System reset.
Maintaining Your Air Bag System
WARNING!
Modifications to any part of the air bag
system could cause it to fail when you need
it. You could be injured if the air bag system
is not there to protect you. Do not modify
the components or wiring, including adding
any kind of badges or stickers to the
steering wheel hub trim cover or the upper
passenger side of the instrument panel. Do
not modify the front fascia/bumper, vehicle
body structure, or add aftermarket side
steps or running boards.
It is dangerous to try to repair any part of
the air bag system yourself. Be sure to tell
anyone who works on your vehicle that it
has an air bag system.
Do not attempt to modify any part of your
air bag system. The air bag may inflate acci-
dentally or may not function properly if
modifications are made. Take your vehicle
to an authorized dealer for any air bag
system service. If your seat, including your
trim cover and cushion, needs to be
serviced in any way (including removal or
loosening/tightening of seat attachment
bolts), take the vehicle to an authorized
dealer. Only manufacturer approved seat
accessories may be used. If it is necessary
to modify the air bag system for persons
with disabilities, contact an authorized
dealer.
WARNING! (Continued)

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412SERVICING AND MAINTENANCE
(Continued)
Engine Air Cleaner Filter Installation
NOTE:
Inspect and clean the housing if dirt or debris is
present before replacing the engine air cleaner
filter.

1. Install the engine air cleaner filter into the housing assembly with the engine air
cleaner filter inspection surface facing
downward.

2. Install the engine air cleaner filter cover onto the housing assembly.
3. Tighten the fasteners (six) on the engine air cleaner filter assembly.
DRAINING FUEL/WATER SEPARATOR
F
ILTER — DIESEL ENGINE
The fuel/water separator filter housing is
located inside the frame rail, behind the left
front wheel. The best access to this water drain
valve is from under the vehicle. If water is detected in the water separator while
the engine is running, or while the ignition
switch is in the ON/RUN position, the “Water In
Fuel Indicator Light” will illuminate and an
audible chime will be heard. At this point, you
should stop the engine and drain the water from
the filter housing.

Fuel Filter Assembly
If the “Water In Fuel Indicator Light” comes on
and a single chime is heard while you are
driving, or with the ignition in the ON position,
there may be a problem with your water
separator wiring or sensor. See an authorized
dealer for service.
Upon proper draining of the water from the fuel
filter, the “Water In Fuel Indicator Light” will
remain illuminated for approximately 10
seconds. If the water was drained while the
engine was running, the “Water In Fuel Indicator
Light” may remain on for approximately three
minutes.
NOTE:
Care should be taken in disposing of used fluids
from your vehicle. Used fluids, indiscriminately
discarded, can present a problem to the envi
-
ronment. Contact an authorized dealer, service
station, or government agency for advice on
recycling programs and for where used fluids
and filters can be properly disposed of in your
area.
CAUTION!
Do not drain the fuel/water separator filter
when the engine is running.
Diesel fuel will damage blacktop paving
surfaces. Drain the filter into an appro-
priate container.
1 — Water In Fuel Drain Valve
CAUTION! (Continued)CAUTION!
If the “Water In Fuel Indicator Light” remains
on, DO NOT START the engine before you
drain water from the fuel filter to avoid engine
damage.

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SERVICING AND MAINTENANCE439
Replacing Exterior Bulbs
Base Quad: Low Beam Headlamp, High Beam
Headlamp, Front Park And Turn — If Equipped
Low Beam
See below steps to replace:

1. Open the hood.

2. Disconnect and isolate the negative battery
cable.
3. Locate the low beam access cover, which can be found on the back side of the
headlamps.

Low Beam Headlight Cover
NOTE:
It may be necessary to remove/reposition Air
Cleaner Assembly to access passenger side
headlamp/side marker light bulbs.
4. Disengage the bulb access cover by rotating
counterclockwise.
5. Disconnect the internal lamp wiring harness connector from the low beam bulb.
6. Rotate the bulb counterclockwise a quarter turn to unlock the bulb from the lamp.
7. Pull the bulb straight out from the housing.
8. Reverse the procedure for installation of new bulb and covers. High Beam

High Beam Headlight Cover

See below steps to replace:

1. Open the hood.

2. Disconnect and isolate the negative battery cable.
3. Locate the high beam access cover, which can be found on the back side of the
headlamps.
NOTE:
It may be necessary to remove/reposition Air
Cleaner Assembly to access passenger side
headlamp/side marker light bulbs.
CAUTION!
Do not contaminate the bulb glass by
touching it with your fingers or by allowing it
to contact other oily surfaces. Shortened
bulb life will result.
Always use the correct bulb size and type
for replacement. An incorrect bulb size or
type may overheat and cause damage to
the lamp, the bulb socket, or the lamp
wiring.
8

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