warning Ram 3500 2020 Repair Manual

138GETTING TO KNOW YOUR INSTRUMENT PANEL
YELLOW INDICATOR LIGHTS
Forward Collision Warning Off Indicator
Light — If Equipped
This indicator light illuminates to
indicate that Forward Collision
Warning is off.
Refer to “Auxiliary Driving Systems” in “Safety”
for further information.
Air Suspension Payload Protection
Indicator Light — If Equipped
This indicator light will illuminate to
indicate that the maximum payload
may have been exceeded or load
leveling cannot be achieved at its
current ride height. Protection Mode will
automatically be selected in order to “protect”
the air suspension system, air suspension
adjustment is limited due to payload.
TOW/HAUL Indicator Light
This indicator light will illuminate
when TOW/HAUL mode is selected.
Refer to “Trailer Towing” in “Starting
And Operating” for further information.
Cargo Light — If Equipped
This indicator light will illuminate
when the cargo light is activated by
pushing the cargo light button on the
headlight switch.
Cold Ambient Derate Mode Indicator Light
— If Equipped
This indicator light will illuminate
when a derate (engine power
reduction) is activated for protection
of the turbocharger in cold ambient
temperatures.
For further information, refer to “Instrument
Cluster Display” in “Getting To Know Your
Instrument Panel”.
Diesel Exhaust Brake Indicator Light — If
Equipped
This indicator light will illuminate
when the Diesel Exhaust Brake has
been activated, and is in full strength
mode.
Refer to “Diesel Exhaust Brake (Engine
Braking)” in “Starting And Operating” for further
information.
Sway Bar Indicator Light — If Equipped
This indicator light will illuminate
when the front sway bar is
disconnected.
Refer to “Stabilizer/Sway Bar System — Power
Wagon Only” in “Starting And Operating” for
further information.
Snowplow Mode Indicator Light — If
Equipped
This indicator light will illuminate
when Snowplow Mode has been
activated.
Refer to “Snowplow” in “Starting And
Operating” for further information.
Air Suspension Alternate Trailer Height
Indicator Light — If Equipped
This light will illuminate when the air
suspension system is set to the
Alternate Trailer Height setting.
Refer to “Air Suspension System — If Equipped”
in “Starting And Operating” for further
information.

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GETTING TO KNOW YOUR INSTRUMENT PANEL141
to provide visual and torque warnings if an
unintentional lane departure occurs.
Refer to “LaneSense — If Equipped” in “Starting
And Operating” for further information.
Front Fog Indicator Light — If Equipped
This indicator light will illuminate
when the front fog lights are on.
Refer to “Exterior Lights” in “Getting
To Know Your Vehicle” for further information.
Turn Signal Indicator Lights
When the left or right turn signal is
activated, the turn signal indicator will
flash independently and the
corresponding exterior turn signal
lamps will flash. Turn signals can be activated
when the multifunction lever is moved down
(left) or up (right).
NOTE:
A continuous chime will sound if the vehicle is
driven more than 1 mile (1.6 km) with either
turn signal on.
Check for an inoperative outside light bulb if
either indicator flashes at a rapid rate.

If equipped with fog lamps, the fog lamp on the
side of the activated turn signal will also illumi -
nate to provide additional light when turning.

Cruise Control Set Indicator Light — If
Equipped
This indicator light will illuminate
when the cruise control is set to the
desired speed. Refer to “Speed
Control” in “Starting And Operating”
for further information.
WHITE INDICATOR LIGHTS

Adaptive Cruise Control (ACC) Ready Light
— If Equipped

This light will illuminate when the vehicle
equipped with Adaptive Cruise Control
(ACC) has been turned on but not set.

Refer to “Adaptive Cruise Control (ACC) — If
Equipped” in “Starting And Operating” for
further information.
Cruise Control Ready Indicator

This indicator light will illuminate
when the cruise control is ready,
but not set. Refer to “Speed Control”
in “Starting And Operating” for
further information.

Hill Descent Control (HDC) Indicator Light
— If Equipped
This indicator shows when the Hill
Descent Control (HDC) feature is
turned on. The lamp will be on solid
when HDC is armed. HDC can only be
armed when the transfer case is in the “4WD
LOW” position and the vehicle speed is less
then 20 mph (32 km/h). If these conditions are
not met while attempting to use the HDC
feature, the HDC indicator light will flash on/off.
LaneSense Indicator Light — If Equipped
When the LaneSense system is ON,
but not armed, the LaneSense
indicator light illuminates solid white.
This occurs when only left, right, or
neither lane line has been detected. If a single
lane line is detected, the system is ready to
provide only visual warnings if an unintentional
lane departure occurs on the detected lane line.
Refer to “LaneSense — If Equipped” in “Starting
And Operating” for further information.
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142GETTING TO KNOW YOUR INSTRUMENT PANEL
BLUE INDICATOR LIGHTS
High Beam Indicator Light
This indicator light will illuminate to
indicate that the high beam
headlights are on. With the low beams
activated, push the multifunction
lever forward (toward the front of the vehicle) to
turn on the high beams. Pull the multifunction
lever rearward (toward the rear of the vehicle) to
turn off the high beams. If the high beams are
off, pull the lever toward you for a temporary
high beam on, "flash to pass" scenario.
ONBOARD DIAGNOSTIC SYSTEM — OBD II
Your vehicle is equipped with a sophisticated
Onboard Diagnostic system called OBD II. This
system monitors the performance of the
emissions, engine, and transmission control
systems. When these systems are operating
properly, your vehicle will provide excellent
performance and fuel economy, as well as
engine emissions well within current
government regulations.
If any of these systems require service, the OBD
II system will turn on the Malfunction Indicator
Light (MIL). It will also store diagnostic codes and other information to assist your service
technician in making repairs. Although your
vehicle will usually be drivable and not need
towing, see an authorized dealer for service as
soon as possible.
ONBOARD DIAGNOSTIC SYSTEM
(OBD II) C
YBERSECURITY
Your vehicle is required to have an Onboard
Diagnostic system (OBD II) and a connection
port to allow access to information related to
the performance of your emissions controls. Authorized service technicians may need to
access this information to assist with the
diagnosis and service of your vehicle and
emissions system.
For further information, refer to “Cybersecurity”
in “Multimedia”.
CAUTION!
Prolonged driving with the MIL on could
cause further damage to the emission
control system. It could also affect fuel
economy and driveability. The vehicle must
be serviced before any emissions tests can
be performed.
If the MIL is flashing while the vehicle is
running, severe catalytic converter damage
and power loss will soon occur. Immediate
service is required.
WARNING!
ONLY an authorized service technician
should connect equipment to the OBD II
connection port in order to read the VIN,
diagnose, or service your vehicle.
If unauthorized equipment is connected to
the OBD II connection port, such as a
driver-behavior tracking device, it may:
Be possible that vehicle systems,
including safety related systems, could
be impaired or a loss of vehicle control
could occur that may result in an acci
-
dent involving serious injury or death.
Access, or allow others to access, infor -
mation stored in your vehicle systems,
including personal information.

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144 (Continued)
SAFETY
SAFETY FEATURES
ANTI-LOCK BRAKE SYSTEM (ABS)
The Anti-Lock Brake System (ABS) provides
increased vehicle stability and brake
performance under most braking conditions.
The system automatically prevents wheel lock,
and enhances vehicle control during braking.
The ABS performs a self-check cycle to ensure
that the ABS is working properly each time the
vehicle is started and driven. During this
self-check, you may hear a slight clicking sound
as well as some related motor noises.
ABS is activated during braking when the
system detects one or more wheels begin to
lock. Road conditions such as ice, snow, gravel,
bumps, railroad tracks, loose debris, or panic
stops may increase the likelihood of ABS
activation(s).You also may experience the following when
ABS activates:
The ABS motor noise (it may continue to run
for a short time after the stop)
The clicking sound of solenoid valves
Brake pedal pulsations
A slight drop of the brake pedal at the end of
the stop
These are all normal characteristics of ABS.
WARNING!
The ABS contains sophisticated electronic
equipment that may be susceptible to inter -
ference caused by improperly installed or
high output radio transmitting equipment.
This interference can cause possible loss of
anti-lock braking capability. Installation of
such equipment should be performed by
qualified professionals.
Pumping of the Anti-Lock Brakes will
diminish their effectiveness and may lead
to a collision. Pumping makes the stopping
distance longer. Just press firmly on your
brake pedal when you need to slow down or
stop.
The ABS cannot prevent the natural laws of
physics from acting on the vehicle, nor can
it increase braking or steering efficiency
beyond that afforded by the condition of the
vehicle brakes and tires or the traction
afforded.
The ABS cannot prevent collisions,
including those resulting from excessive
speed in turns, following another vehicle
too closely, or hydroplaning.
The capabilities of an ABS equipped vehicle
must never be exploited in a reckless or
dangerous manner that could jeopardize
the user’s safety or the safety of others.
WARNING! (Continued)

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SAFETY145
ABS is designed to function with the Original
Equipment Manufacturer (OEM) tires.
Modification may result in degraded ABS
performance.
Anti-Lock Brake Warning Light
The yellow “Anti-Lock Brake Warning Light” will
turn on when the ignition is placed in the ON/
RUN mode and may stay on for as long as four
seconds.
If the “Anti-Lock Brake Warning Light” remains
on or comes on while driving, it indicates that
the anti-lock portion of the brake system is not
functioning and that service is required.
However, the conventional brake system will
continue to operate normally if the “Anti-Lock
Brake Warning Light” is on.
If the “Anti-Lock Brake Warning Light” is on, the
brake system should be serviced as soon as
possible to restore the benefits of anti-lock
brakes. If the “Anti-Lock Brake Warning Light”
does not come on when the ignition is placed in
the ON/RUN mode, have the light repaired as
soon as possible.
ELECTRONIC BRAKE CONTROL (EBC)
S
YSTEM
Your vehicle is equipped with an advanced
Electronic Brake Control (EBC) system . This
system includes Electronic Brake Force
Distribution (EBD), Anti-Lock Brake System
(ABS), Brake Assist System (BAS), Hill Start
Assist (HSA), Traction Control System (TCS),
Electronic Stability Control (ESC), and Electronic
Roll Mitigation (ERM). These systems work
together to enhance both vehicle stability and
control in various driving conditions.
Your vehicle may also be equipped with Trailer
Sway Control (TSC) and Hill Descent Control
(HDC).
Brake Assist System (BAS)
The Brake Assist System (BAS) is designed to
optimize the vehicle’s braking capability during
emergency braking maneuvers. The system
detects an emergency braking situation by
sensing the rate and amount of brake
application and then applies optimum pressure
to the brakes. This can help reduce braking
distances. The BAS complements the Anti-Lock
Brake System (ABS). Applying the brakes very
quickly results in the best BAS assistance. To receive the benefit of the system, you must
apply continuous braking pressure during the
stopping sequence (do not “pump” the brakes).
Do not reduce brake pedal pressure unless
braking is no longer desired. Once the brake
pedal is released, the BAS is deactivated.
Brake System Warning Light
The red “Brake System Warning Light” will turn
on when the ignition is placed in the ON/RUN
mode and may stay on for as long as four
seconds.
WARNING!
The Brake Assist System (BAS) cannot
prevent the natural laws of physics from
acting on the vehicle, nor can it increase the
traction afforded by prevailing road
conditions. BAS cannot prevent collisions,
including those resulting from excessive
speed in turns, driving on very slippery
surfaces, or hydroplaning. The capabilities of
a BAS-equipped vehicle must never be
exploited in a reckless or dangerous manner,
which could jeopardize the user's safety or
the safety of others.
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146SAFETY
(Continued)
If the “Brake System Warning Light” remains on
or comes on while driving, it indicates that the
brake system is not functioning properly and
that immediate service is required. If the “Brake
System Warning Light” does not come on when
the ignition is placed in the ON/RUN mode,
have the light repaired as soon as possible.
Electronic Brake Force Distribution (EBD)
This function manages the distribution of the
braking torque between the front and rear axles
by limiting braking pressure to the rear axle.
This is done to prevent overslip of the rear
wheels to avoid vehicle instability, and to
prevent the rear axle from entering Anti-Lock
Brake System (ABS) before the front axle.
Electronic Stability Control (ESC)
This system enhances directional control and
stability of the vehicle under various driving
conditions. Electronic Stability Control (ESC)
corrects for oversteering or understeering of the
vehicle by applying the brake of the appropriate
wheel(s) to assist in counteracting the oversteer
or understeer condition. Engine power may also
be reduced to help the vehicle maintain the
desired path.ESC uses sensors in the vehicle to determine
the vehicle path intended by the driver and
compares it to the actual path of the vehicle.
When the actual path does not match the
intended path, ESC applies the brake of the
appropriate wheel to assist in counteracting the
oversteer or understeer condition.

Oversteer — when the vehicle is turning
more than appropriate for the steering
wheel position.
Understeer — when the vehicle is turning
less than appropriate for the steering wheel
position.

The “ESC Activation/Malfunction Indicator
Light” located in the instrument cluster will start
to flash as soon as the ESC system becomes
active. The “ESC Activation/Malfunction
Indicator Light” also flashes when the TCS is
active. If the “ESC Activation/Malfunction
Indicator Light” begins to flash during
acceleration, ease up on the accelerator and
apply as little throttle as possible. Be sure to
adapt your speed and driving to the prevailing
road conditions.
WARNING!
Electronic Stability Control (ESC) cannot
prevent the natural laws of physics from
acting on the vehicle, nor can it increase
the traction afforded by prevailing road
conditions. ESC cannot prevent accidents,
including those resulting from excessive
speed in turns, driving on very slippery
surfaces, or hydroplaning. ESC also cannot
prevent accidents resulting from loss of
vehicle control due to inappropriate driver
input for the conditions. Only a safe, atten -
tive, and skillful driver can prevent acci -
dents. The capabilities of an ESC equipped
vehicle must never be exploited in a reck -
less or dangerous manner which could
jeopardize the user’s safety or the safety of
others.

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SAFETY147
ESC Operating Modes
NOTE:
Depending upon model and mode of operation,
the ESC system may have multiple operating
modes. ESC On
This is the normal operating mode for the ESC.
Whenever the vehicle is started, the ESC system
will be in this mode. This mode should be used
for most driving conditions. Alternate ESC
modes should only be used for specific reasons
as noted in the following paragraphs.
Partial Off
The “Partial Off” mode is intended for times
when a more spirited driving experience is
desired. This mode may modify TCS and ESC
thresholds for activation, which allows for more
wheel spin than normally allowed. This mode
may be useful if the vehicle becomes stuck.
To enter the “Partial Off” mode, momentarily
push the “ESC OFF” switch and the “ESC OFF
Indicator Light” will illuminate. To turn the ESC
on again, momentarily push the “ESC OFF”
switch and the “ESC OFF Indicator Light” will
turn off.
NOTE:
For vehicles with multiple partial ESC modes, a
momentary button push will toggle the ESC
mode. Multiple momentary button pushes may
be required to return to ESC On.
Vehicle modifications, or failure to properly
maintain your vehicle, may change the
handling characteristics of your vehicle,
and may negatively affect the performance
of the ESC system. Changes to the steering
system, suspension, braking system, tire
type and size or wheel size may adversely
affect ESC performance. Improperly
inflated and unevenly worn tires may also
degrade ESC performance. Any vehicle
modification or poor vehicle maintenance
that reduces the effectiveness of the ESC
system can increase the risk of loss of
vehicle control, vehicle rollover, personal
injury and death.
WARNING!
(Continued)
WARNING!
When in “Partial Off” mode, the TCS func -
tionality of ESC, (except for the limited slip
feature described in the TCS section), has
been disabled and the “ESC Off Indicator
Light” will be illuminated. When in “Partial
Off” mode, the engine power reduction
feature of TCS is disabled, and the
enhanced vehicle stability offered by the
ESC system is reduced.
Trailer Sway Control (TSC) is disabled when
the ESC system is in the “Partial Off” mode.
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148SAFETY
Full Off — If Equipped
This mode is intended for off-highway or
off-road use only and should not be used on any
public roadways. In this mode, TCS and ESC
features are turned off. To enter the “Full Off”
mode, push and hold the “ESC OFF” switch for
five seconds while the vehicle is stopped with
the engine running. After five seconds, a chime
will sound, the “ESC OFF Indicator Light” will
illuminate, and the “ESC OFF” message will
display in the instrument cluster. To turn ESC on
again, momentarily push the “ESC OFF” switch.
NOTE:
System may switch from ESC “Full Off” to
“Partial Off” mode when vehicle exceeds a
predetermined speed. When the vehicle speed
slows below the predetermined speed the
system will return to ESC “Full Off”.
ESC modes may also be affected by drive
modes (if equipped).ESC Activation/Malfunction Indicator Light
And ESC OFF Indicator Light
The “ESC Activation/Malfunction
Indicator Light” in the instrument
cluster will come on when the ignition
is turned to the ON mode. It should go
out with the engine running. If the “ESC
Activation/Malfunction Indicator Light” comes
on continuously with the engine running, a
malfunction has been detected in the ESC
system. If this light remains on after several
ignition cycles, and the vehicle has been driven
several miles (kilometers) at speeds greater
than 30 mph (48 km/h), see an authorized
dealer as soon as possible to have the problem
diagnosed and corrected.
The “ESC Activation/Malfunction Indicator
Light” (located in the instrument cluster) starts
to flash as soon as the tires lose traction and
the ESC system becomes active. The “ESC
Activation/Malfunction Indicator Light” also
flashes when TCS is active. If the “ESC
Activation/Malfunction Indicator Light” begins
WARNING!
In the ESC “Full Off” mode, the engine
torque reduction and stability features are
disabled. Therefore, enhanced vehicle
stability offered by the ESC system is
unavailable. In an emergency evasive
maneuver, the ESC system will not engage
to assist in maintaining stability. ESC “Full
Off” mode is intended for off-highway or
off-road use only.
The Electronic Stability Control (ESC)
cannot prevent the natural laws of physics
from acting on the vehicle, nor can it
increase the traction afforded by prevailing
road conditions. ESC cannot prevent all
accidents, including those resulting from
excessive speed in turns, driving on very
slippery surfaces, or hydroplaning. ESC also
cannot prevent collisions.

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SAFETY149
to flash during acceleration, ease up on the
accelerator and apply as little throttle as
possible. Be sure to adapt your speed and
driving to the prevailing road conditions.
NOTE:
The “ESC Activation/Malfunction Indicator
Light” and the “ESC OFF Indicator Light”
come on momentarily each time the ignition
is placed in the ON position.
Each time the ignition is placed in the ON
position, the ESC system will be on even if it
was turned off previously.
The ESC system will make buzzing or clicking
sounds when it is active. This is normal; the
sounds will stop when ESC becomes inactive
following the maneuver that caused the ESC
activation.
The “ESC OFF Indicator Light”
indicates the customer has elected to
have the Electronic Stability Control
(ESC) in a reduced mode.
Electronic Roll Mitigation (ERM)
This system anticipates the potential for wheel
lift by monitoring the driver’s steering wheel
input and the speed of the vehicle. When
Electronic Roll Mitigation (ERM) determines
that the rate of change of the steering wheel
angle and vehicle’s speed are sufficient to
potentially cause wheel lift, it then applies the
appropriate brake and may also reduce engine
power to lessen the chance that wheel lift will
occur. ERM can only reduce the chance of
wheel lift occurring during severe or evasive
driving maneuvers; it cannot prevent wheel lift
due to other factors, such as road conditions,
leaving the roadway, or striking objects or other
vehicles.
NOTE:
ERM is disabled anytime the ESC is in “Full Off”
mode (if equipped). Refer to “Electronic Stability
Control (ESC)” in this section for a complete
explanation of the available ESC modes.
Hill Descent Control (HDC) — If Equipped
Hill Descent Control (HDC) is intended for low
speed off road driving while in 4L Range. HDC
maintains vehicle speed while descending hills
during various driving situations. HDC controls
vehicle speed by actively controlling the brakes.
WARNING!
Many factors, such as vehicle loading, road
conditions and driving conditions, influence
the chance that wheel lift or rollover may
occur. ERM cannot prevent all wheel lift or roll
overs, especially those that involve leaving
the roadway or striking objects or other
vehicles. The capabilities of an
ERM-equipped vehicle must never be
exploited in a reckless or dangerous manner
which could jeopardize the user's safety or
the safety of others.
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SAFETY151
Disabling HDC
HDC will be deactivated and disabled if any of
the following conditions occur:
The driver pushes the HDC switch.
The driveline is shifted out of 4L Range.
The parking brake is applied.
The driver door opens.
The vehicle is driven greater than 20 mph
(32 km/h) for greater than 70 seconds.
The vehicle is driven greater than 40 mph
(64 km/h) (HDC exits immediately).
HDC detects excessive brake temperature.
Feedback To The Driver
The instrument cluster has an HDC icon and the
HDC switch has an LED icon, which offers
feedback to the driver about the state HDC is in.
The cluster icon and switch lamp will illumi -
nate and remain on solid when HDC is
enabled or activated. This is the normal oper -
ating condition for HDC.
The cluster icon and switch lamp will flash for
several seconds then extinguish when the
driver pushes the HDC switch but enable
conditions are not met.
The cluster icon and switch lamp will flash for
several seconds then extinguish when HDC
disables due to excess speed.

The cluster icon and switch lamp will flash when
HDC deactivates due to overheated brakes. The
flashing will stop and HDC will activate again
once the brakes have cooled sufficiently.

Hill Start Assist (HSA)
The Hill Start Assist (HSA) system is designed to
mitigate roll back from a complete stop while on
an incline. If the driver releases the brake while
stopped on an incline, HSA will continue to hold
the brake pressure for a short period. If the driver does not apply the throttle before this
time expires, the system will release brake
pressure and the vehicle will roll down the hill as
normal.
The following conditions must be met in order
for HSA to activate:
The feature must be enabled.
The vehicle must be stopped.
The park brake must be off.
The driver door must be closed.
The vehicle must be on a sufficient grade.
The gear selection must match vehicle uphill
direction (i.e., vehicle facing uphill is in
forward gear; vehicle backing uphill is in
REVERSE (R) gear).
HSA will work in REVERSE gear and all
forward gears. The system will not activate if
the transmission is in PARK or NEUTRAL (N).
For vehicles equipped with a manual trans
-
mission, if the clutch is pressed, HSA will
remain active.
WARNING!
HDC is only intended to assist the driver in
controlling vehicle speed when descending
hills. The driver must remain attentive to the
driving conditions and is responsible for
maintaining a safe vehicle speed.
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