2021 RAM 1500 ac wiring harness

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

21_DT_OM_EN_USC_t.book Page 88

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

21_DT_OM_EN_USC_t.book Page 225

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

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

21_DT_OM_EN_USC_t.book Page 439

440SERVICING AND MAINTENANCE
4. Reach behind the headlamp and disengage
the access cover by rotating counter -
clockwise.
5. Disconnect the internal lamp wiring harness connector from the high 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 cover. Front Park And Turn
See below steps to replace:

1. Open the hood.

2. Disconnect and isolate the negative battery
cable.
3. Locate the park and turn socket, which can be found on the back side of the
headlamps.

Park And Turn Socket

4. Reach behind the headlamp and unlock the park and turn socket from the lamp by
rotating counterclockwise a quarter turn.
5. Pull the bulb straight out from the housing. 6. Separate the bulb from the socket without
twisting.
7. Reverse the procedure for installation of new bulb and covers.
Side Marker Lamp
See below steps to replace:

1. Open the hood.

2. Disconnect and isolate the negative battery cable.
3. Locate the side marker lamp, which can be found on the back side of the headlamps.

Side Marker Lamp

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.

21_DT_OM_EN_USC_t.book Page 440

SERVICING AND MAINTENANCE441
4. Disengage the side marker socket by
rotating counterclockwise a quarter turn.
5. Pull the socket and bulb straight out from the housing.
6. Separate the bulb from the socket without twisting.
7. Reverse the procedure for installation of new bulb and covers.
Fog Lamps — If Equipped
Please see an authorized dealer for service on
LED and Halogen front fog lamps.
Halogen
See below steps to replace:

1. Reach under and behind the front fascia/ bumper to access the back of the front fog
lamp housing.

2. Disconnect the fog lamp wiring harness connector from the fog lamp bulb.
Fog Lamp Bulb

3. Rotate the bulb counterclockwise a quarter turn to unlock the bulb from the housing.
4. Pull the bulb straight out from the housing.
5. Reverse the procedure to install the bulb and cover. Rear Tail/Stop, Turn Signal And Backup Lamps
See below steps to replace:

1. Remove the two screws and push pins
retainers that pass through the bed sheet
metal.

Tail Lamp Locations

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.
1 — Tail Lamp
2 — Fasteners
3 — Push - Pin Retainers
8

21_DT_OM_EN_USC_t.book Page 441

442SERVICING AND MAINTENANCE
2. Pull the outboard side of the lamp rearward
far enough to unsnap the two receptacles
on the outboard side of the lamp housing
from the two plastic snap post retainers in
the outer box side panel.

Tail Lamp Removal

3. Disconnect the wiring harness connectors from the bulb socket.

Wiring Harness Connector
4. Rotate the bulb socket counterclockwise a
quarter turn to unlock it from the housing.
5. Pull the bulb straight out of the socket.
6. Reverse the procedure to install the bulb and housing.
Center High Mounted Stop Lamp (CHMSL)
With Cargo Lamp
See below steps to replace:

1. Remove the four screws holding the housing/lens to the body as shown.
CHMSL Mounting Screw Locations

2. Separate the connector holding the housing and wiring harness to the body.

CHMSL Bulb Location

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.

21_DT_OM_EN_USC_t.book Page 442