2021 RAM PROMASTER trailer

82STARTING AND OPERATING
(Continued)
Towing Requirements — Tires
Do not attempt to tow a trailer while using a
compact spare tire.
Do not drive more than 50 mph (80 km/h) when towing while using a full size spare tire.
Proper tire inflation pressures are essential
to the safe and satisfactory operation of your
vehicle.
Check the trailer tires for proper tire inflation
pressures before trailer usage.
Check for signs of tire wear or visible tire
damage before towing a trailer.
Replacing tires with a higher load carrying
capacity will not increase the vehicle's GVWR
and GAWR limits.
For further information Ú page 240.
Towing Requirements — Trailer Brakes
Do not interconnect the hydraulic brake
system or vacuum system of your vehicle
with that of the trailer. This could cause inad -
equate braking and possible personal injury.
WARNING!
Make certain that the load is secured in the
trailer and will not shift during travel. When
trailering cargo that is not fully secured,
dynamic load shifts can occur that may be
difficult for the driver to control. You could
lose control of your vehicle and have a
collision.
When hauling cargo or towing a trailer, do
not overload your vehicle or trailer. Over -
loading can cause a loss of control, poor
performance or damage to brakes, axle,
engine, transmission, steering, suspension,
chassis structure or tires.
Safety chains must always be used
between your vehicle and trailer. Always
connect the chains to the hook retainers of
the vehicle hitch. Cross the chains under
the trailer tongue and allow enough slack
for turning corners.
Vehicles with trailers should not be parked
on a grade. When parking, apply the
parking brake on the tow vehicle. Put the
tow vehicle transmission in PARK. For
four-wheel drive vehicles, make sure the
transfer case is not in NEUTRAL. Always,
block or "chock" the trailer wheels.
GCWR must not be exceeded.
Total weight must be distributed between
the tow vehicle and the trailer such that the
following four ratings are not exceeded :
GVWR
GTW
GAWR
Tongue weight rating for the trailer
hitch utilized.
WARNING! (Continued)

21_VF_OM_EN_USC_t.book Page 82

STARTING AND OPERATING83
An electronically actuated trailer brake
controller is required when towing a trailer
with electronically actuated brakes. When
towing a trailer equipped with a hydraulic
surge actuated brake system, an electronic
brake controller is not required.
Trailer brakes are recommended for trailers
over 1,000 lbs (453 kg) and may be required
for any trailer, for example trailers in excess
of 2,000 lbs (907 kg). Trailer brake require -
ments vary by local law, consult local legal
requirements where the trailer is to be towed
for trailer brake requirements.
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- 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 mate 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 after clear from water
area.

Four-Pin Connector

WARNING!
Do not connect trailer brakes to your
vehicle's hydraulic brake lines. It can over -
load your brake system and cause it to fail.
You might not have brakes when you need
them and could have an accident.
Towing any trailer will increase your stop -
ping distance. When towing, you should
allow for additional space between your
vehicle and the vehicle in front of you.
Failure to do so could result in an accident.
CAUTION!
If the trailer weighs more than 1,000 lbs
(453 kg) loaded, it should have its own
brakes and they should be of adequate
capacity. Failure to do this could lead to
accelerated brake lining wear, higher brake
pedal effort, and longer stopping distances.
1 — Ground
2 — Tail Lamp
3 — Left Stop/Turn
4 — Right Stop/Turn
4

21_VF_OM_EN_USC_t.book Page 83

84STARTING AND OPERATING

Seven-Pin Connector

TOWING TIPS
Before towing, practice turning, stopping, and
backing up the trailer in an area located away
from heavy traffic.
Automatic Transmission
The DRIVE range can be selected when towing.
The transmission controls include a drive
strategy to avoid frequent shifting when towing.
However, if frequent shifting does occur while in
DRIVE, select TOW/HAUL mode or select a lower
gear range (using the Electronic Range Select
(ERS) shift control).
NOTE:
Using TOW/HAUL mode or selecting a lower
gear range (using the ERS shift control) while
operating the vehicle under heavy loading
conditions will improve performance and
extend transmission life by reducing excessive
shifting and heat build-up. This action will also
provide better engine braking.
When towing a loaded trailer up steep grades at
low speeds, holding your vehicle in FIRST gear
(using the ERS shift control) can help to avoid
transmission overheating.
Tow/Haul Mode
To reduce potential for automatic transmission
overheating, activate TOW/HAUL mode when
driving in hilly areas, or select a lower gear
range (using the Electronic Range Select (ERS)
shift control) on more severe grades.
Cruise Control — If Equipped
Do not use on hilly terrain or with heavy
loads.
When using the Cruise Control, if you experi -
ence speed drops greater than 10 mph
(16 km/h), disengage until you can get back
to cruising speed.
Use Cruise Control in flat terrain and with
light loads to maximize fuel efficiency.
1 — Battery
2 — Backup Lamps
3 — Right Stop/Turn
4 — Electric Brakes
5 — Ground
6 — Left Stop/Turn
7 — Tail Lamp

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STARTING AND OPERATING85
RECREATIONAL TOWING (BEHIND MOTORHOME)
TOWING THIS VEHICLE BEHIND ANOTHER VEHICLE
R
ECREATIONAL TOWING
Recreational towing is allowed ONLY if the front
wheels are OFF the ground. This may be
accomplished using a tow dolly or vehicle
trailer. If using a tow dolly, follow this procedure:

1. Properly secure the dolly to the tow vehicle, following the dolly manufacturer's
instructions.

2. Drive the front wheels onto the tow dolly. 3. Firmly apply the parking brake. Place the
transmission in PARK.
4. Properly secure the front wheels to the dolly, following the dolly manufacturer's
instructions.
5. Release the parking brake.
Towing Condition Wheels OFF the Ground Automatic Transmission
Flat Tow NONENOT ALLOWED
Dolly Tow Front
OK
Rear NOT ALLOWED
On Trailer ALLOK
NOTE:
When towing your vehicle, always follow applicable state and provincial laws. Contact state and provincial Highway Safety offices for additional details.
CAUTION!
DO NOT flat tow this vehicle. Damage to the
drivetrain will result. If this vehicle requires
towing, make sure the drive wheels are OFF
the ground.
Towing this vehicle in violation of the above
requirements can cause severe transmis -
sion damage. Damage from improper
towing is not covered under the New
Vehicle Limited Warranty.
4

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150SAFETY
ELECTRONIC BRAKE CONTROL (EBC)
S
YSTEM
Your vehicle is equipped with an advanced
Electronic Brake Control (EBC) system that
includes the Brake Assist System (BAS) and
Electronic Stability Control (ESC), Hill Start
Assist (HSA), Traction Control System (TCS), and
Trailer Sway Control (TSC). These systems
complement the Anti-Lock Brake System (ABS)
by optimizing the vehicle braking capability
during emergency braking maneuvers.
Brake Assist System (BAS)
The 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.
Crosswind Assist (CWA)
CWA helps keep your vehicle from drifting out of
its lane due to unexpected crosswinds by
means of targeted braking of individual wheels.
The system will provide automatic stability
assistance to counteract the effect of strong
side wind. If a strong lateral wind is detected,
front and rear brakes on the affected side are applied, creating a steering effect that mitigates
the cross wind influence. During system
intervention, the driver should perceive the
natural stable handling feel of the vehicle.
Crosswind Assist will activate automatically
when the vehicle reaches speeds above
approximately 43 mph (70 km/h). When the
system is activated, the ESC Warning Light in
the instrument cluster will blink to warn the
driver.
Electronic Stability Control (ESC)
ESC enhances directional control and stability
of the vehicle under various driving conditions.
ESC corrects for over/under steering of the
vehicle by applying the brake of the appropriate
wheel(s) to counteract the above conditions.
Engine power may also be reduced to help the
vehicle maintain the desired path.
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.
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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152SAFETY
ESC Partial Off
This mode is entered by momentarily pushing
the ESC OFF button.
When in the “Partial Off” mode, the TCS portion
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 the “Partial Off” mode,
ESC will operate without engine torque
management. This mode is intended to be used
if the vehicle is in deep snow, sand or gravel
conditions and more wheel spin than ESC would
normally allow is required to gain traction.
To turn ESC on again, momentarily push the
ESC OFF button. This will restore the normal
“ESC On” mode of operation. NOTE:
To improve the vehicle's traction when driving
with snow chains, or starting off in deep snow,
sand or gravel, it may be desirable to switch to
the “Partial Off” mode by pushing the ESC OFF
button. Once the situation requiring ESC to be
switched to the “Partial Off” mode is overcome,
turn ESC back on by momentarily pushing the
ESC OFF button. This may be done while the
vehicle is in motion.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
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 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!
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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SAFETY153
The ESC OFF Indicator Light indicates
that the Electronic Stability Control
(ESC) is in a reduced mode.
NOTE:
The ESC Activation/Malfunction Indicator
Light and the ESC OFF Indicator Light come
on momentarily each time the ignition switch
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.
Hill Start Assist (HSA)
The HSA system is designed to assist the driver
when starting a vehicle from a stop on a hill.
HSA will maintain the level of brake pressure
the driver applied for a short period of time after
the driver takes their foot off of the brake pedal.
If the driver does not apply the throttle during
this short period of time, the system will release
brake pressure and the vehicle will roll down the
hill. The system will release brake pressure in
proportion to the amount of throttle applied as
the vehicle starts to move in the intended
direction of travel.
HSA Activation Criteria
The following criteria must be met in order for
HSA to activate:
The vehicle must be stopped.
The vehicle must be on a 6% (approximate)
grade or greater hill.

Gear selection matches vehicle uphill direction
(i.e., vehicle facing uphill is in forward gear;
vehicle backing uphill is in REVERSE gear).

HSA will work in REVERSE and all forward gears
when the activation criteria have been met. The
system will not activate if the vehicle is placed
in NEUTRAL or PARK.
WARNING!
There may be situations on minor hills with a
loaded vehicle, or while pulling a trailer, when
the system will not activate and slight rolling
may occur. This could cause a collision with
another vehicle or object. Always remember
the driver is responsible for braking the
vehicle.
6

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154SAFETY
Towing With HSA
HSA will also provide assistance to mitigate roll
back while towing a trailer.
Traction Control System (TCS)
TCS monitors the amount of wheel spin of each
of the driven wheels. If wheel spin is detected,
brake pressure is applied to the slipping
wheel(s) and engine power is reduced, to
provide enhanced acceleration and stability. A
feature of the TCS, Brake Limited Differential
(BLD), functions similarly to a limited slip
differential and controls the wheel spin across a
driven axle. If one wheel on a driven axle is
spinning faster than the other, the system will
apply the brake of the spinning wheel. This will
allow more engine torque to be applied to the
wheel that is not spinning. This feature remains
active even if the ESC is in the “Partial Off”
mode.
The ESC Activation/Malfunction Indicator Light
(in the instrument cluster) will start to flash as
soon as the tires lose traction and the wheels
begin to spin. This indicates that the TCS is
active. If the indicator light flashes 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, and do not switch off the ESC
or TCS.
Trailer Sway Control (TSC) — If Equipped
TSC uses sensors in the vehicle to recognize an
excessively swaying trailer and will take the
appropriate actions to attempt to stop the sway.
The system may reduce engine power and apply
the brake of the appropriate wheel(s) to
counteract the sway of the trailer.
WARNING!
If you use a trailer brake controller with your
trailer, the trailer brakes may be activated
and deactivated with the brake switch. If
so, there may not be enough brake pres -
sure to hold both the vehicle and the trailer
on a hill when the brake pedal is released.
In order to avoid rolling down an incline
while resuming acceleration, manually acti -
vate the trailer brake or apply more vehicle
brake pressure prior to releasing the brake
pedal.
HSA is not a parking brake. Always apply
the parking brake fully when exiting your
vehicle. Also, be certain to place the trans -
mission in PARK.
Failure to follow these warnings can result
in a collision or serious personal injury.
WARNING!
The TCS cannot prevent the natural laws of
physics from acting on the vehicle, nor can
it increase the traction afforded.
The TCS cannot prevent collisions,
including those resulting from excessive
speed in turns, or hydroplaning.
The capabilities of a TCS-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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