2020 Ram 3500 Chassis Cab air condition

352SERVICING AND MAINTENANCE
Refrigerant Recovery And Recycling
R-1234yf — If Equipped
R-1234yf Air Conditioning Refrigerant is a
hydrofluoroolefin (HFO) that is endorsed by the
Environmental Protection Agency and is an
ozone-friendly substance with a low
global-warming potential. The manufacturer
recommends that air conditioning service be
performed by an authorized dealer using
recovery and recycling equipment.
NOTE:
Use only manufacturer approved A/C system
PAG compressor oil, and refrigerants.
Cabin Filter Replacement (A/C Air Filter)
Refer to the “Maintenance Plan” for the proper
maintenance intervals. The cabin air filter is located in the fresh air inlet
behind the glove compartment. Perform the
following procedure to replace the filter:

1. Open the glove compartment and remove
all contents.

2. With the glove compartment door open, remove the glove compartment tension
tether and tether clip by sliding the clip
toward the face of the glove compartment
door. Lift the clip out of glove compartment
door and release into dash panel.

Right Side Of Glove Compartment
3. There are travel stops on both sides of the
glove compartment. Push inward on right
side of the glove compartment travel stop to
disengage the stop. Then pull the right of
the glove compartment outward (away from
the hinge) to disengaging the right side of
the compartment from the hinge. Continue
by removing the left side from the hinge by
slightly lowering the compartment while
pulling outward until it is completely disen -
gaged from the hinge.

Glove Compartment

WARNING!
Do not remove the cabin air filter while the
vehicle is running, or while the ignition is in
the ACC or ON/RUN mode. With the cabin air
filter removed and the blower operating, the
blower can contact hands and may propel dirt
and debris into your eyes, resulting in
personal injury.
1 — Glove Compartment Door
2 — Glove Compartment Tension Tether
1 — Glove Compartment Travel Stop
2 — Glove Compartment Tension Tether
3 — Glove Compartment Door

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358SERVICING AND MAINTENANCE
Priming If The Engine Has Run Out Of Fuel

1. Add a substantial amount of fuel to the
tank, approximately 2 to 5 gal (8L to 19L).

2. Three priming cycles must be completed. Turn ignition to the RUN position and wait
approximately 30 seconds. This will activate
the in tank fuel pump. Turn the ignition
switch to the off position, and leave off for at
least 30 seconds. Repeat this procedure
three times before cranking the engine.
3. Start the engine using the “Normal Starting” procedure. Refer to “Starting Procedures”
in “Starting and Operating” for further infor -
mation.
4. Once the engine starts, allow the engine to idle for a minimum of 30 seconds. NOTE:
The engine may run rough until the air is forced
from all the fuel lines.
NOTE:
A maximum blend of 5% biodiesel, meeting
ASTM specification D-975 may be used with
your Cummins diesel engine. (Chassis Cab
models not configured with B20 capability.)
A maximum blend of 20% biodiesel, meeting
ASTM specification D-7467 may be used with
your Cummins diesel engine. (Pickup models
and Chassis Cab models configured with B20
capability.)
Use of biodiesel mixture in excess of 20% can
negatively impact the fuel filter's ability to
separate water from the fuel, resulting in
high pressure fuel system corrosion or
damage.
Ethanol blends are not recommended or
approved for use with your Cummins diesel
engine.
In addition, commercially available fuel addi
-
tives are not necessary for the proper opera -
tion of your Cummins diesel engine.
WARNING!
Do not open the high pressure fuel system
with the engine running. Engine operation
causes high fuel pressure. High pressure fuel
spray can cause serious injury or death.
CAUTION!
Do not engage the starter motor for more
than 15 seconds at a time. Allow two minutes
between the cranking intervals.
WARNING!
Do not use alcohol or gasoline as a fuel
blending agent. They can be unstable under
certain conditions and be hazardous or
explosive when mixed with diesel fuel.
CAUTION!
Due to lack of lubricants in alcohol or
gasoline, the use of these fuels can cause
damage to the fuel system.

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360SERVICING AND MAINTENANCE
Body Lubrication
Locks and all body pivot points, including such
items as seat tracks, door hinge pivot points
and rollers, liftgate, tailgate, decklid, sliding
doors and hood hinges, should be lubricated
periodically with a lithium based grease, such
as Mopar Spray White Lube to ensure quiet,
easy operation and to protect against rust and
wear. Prior to the application of any lubricant,
the parts concerned should be wiped clean to
remove dust and grit; after lubricating excess,
oil and grease should be removed. Particular
attention should also be given to hood latching
components to ensure proper function. When
performing other underhood services, the hood
latch, release mechanism and safety catch
should be cleaned and lubricated.
The external lock cylinders should be lubricated
twice a year, preferably in the Autumn and
Spring. Apply a small amount of a high quality
lubricant, such as Mopar Lock Cylinder Lubri -
cant directly into the lock cylinder.
Windshield Wiper Blades
Clean the rubber edges of the wiper blades and
the windshield periodically with a sponge or soft
cloth and a mild nonabrasive cleaner. This will
remove accumulations of salt or road film.
Operation of the wipers on dry glass for long
periods may cause deterioration of the wiper
blades. Always use washer fluid when using the
wipers to remove salt or dirt from a dry wind -
shield.
Avoid using the wiper blades to remove frost or
ice from the windshield. Keep the blade rubber
out of contact with petroleum products such as
engine oil, gasoline, etc.
NOTE:
Life expectancy of wiper blades varies
depending on geographical area and frequency
of use. Poor performance of blades may be
present with chattering, marks, water lines or
wet spots. If any of these conditions are
present, clean the wiper blades or replace as
necessary. The wiper blades and wiper arms should be
inspected periodically, not just when wiper
performance problems are experienced. This
inspection should include the following points:
Wear or uneven edges
Foreign material
Hardening or cracking
Deformation or fatigue
If a wiper blade or wiper arm is damaged,
replace the affected wiper arm or blade with a
new unit. Do not attempt to repair a wiper arm
or blade that is damaged.

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366SERVICING AND MAINTENANCE
Checking Coolant Level — 6.4L Engine
The level of the coolant in the pressurized
coolant bottle should be between the “MIN” and
“MAX” range on the bottle when the engine is
cold.
The radiator normally remains completely full,
so there is no need to remove the cap unless
checking for coolant freeze point or replacing
engine coolant (antifreeze). Advise your service
attendant of this. As long as the engine oper -
ating temperature is satisfactory, the coolant
bottle need only be checked once a month.
When additional engine coolant (antifreeze) is
needed to maintain the proper level, it should
be added to the coolant bottle. Do not overfill.
Points To Remember
NOTE:
When the vehicle is stopped after a few miles/
kilometers of operation, you may observe vapor
coming from the front of the engine compart -
ment. This is normally a result of moisture from
rain, snow, or high humidity accumulating on
the radiator and being vaporized when the ther -
mostat opens, allowing hot engine coolant (anti -
freeze) to enter the radiator. If an examination of your engine compartment
shows no evidence of radiator or hose leaks,
the vehicle may be safely driven. The vapor will
soon dissipate.
Do not overfill the coolant expansion bottle.
Check the coolant freeze point in the radiator
and in the coolant expansion bottle. If engine
coolant (antifreeze) needs to be added, the
contents of the coolant expansion bottle
must also be protected against freezing.
If frequent engine coolant (antifreeze) addi-
tions are required, the cooling system should
be pressure tested for leaks.
Maintain engine coolant (antifreeze) concen
-
tration at a minimum of 50% OAT coolant
(conforming to MS.90032) and distilled
water for proper corrosion protection of your
engine which contains aluminum compo -
nents.
Make sure that the coolant expansion bottle
overflow hoses are not kinked or obstructed.
Keep the front of the radiator clean. If your
vehicle is equipped with air conditioning,
keep the front of the condenser clean.
Do not change the thermostat for Summer or
Winter operation. If replacement is ever
necessary, install ONLY the correct type ther -
mostat. Other designs may result in unsatis -
factory engine coolant (antifreeze)
performance, poor gas mileage, and
increased emissions.
Charge Air Cooler — Inter-Cooler
The charge air cooler is positioned below the
radiator and the air conditioner condenser. Air
enters the engine through the air cleaner and
passes through the turbocharger, where it is
pressurized. This pressurized air rapidly
reaches high temperature. The air is then
directed through a hose to the charge air cooler
and through another hose to the intake mani -
fold of the engine. The air entering the engine
has been cooled by about 50° to 100°F
(10° to 38°C). This cooling process enables
more efficient burning of fuel resulting in fewer
emissions.
To guarantee optimum performance of the
system, keep the surfaces of the charge air
cooler, condenser and radiator clean and free
of debris. Periodically check the hoses leading
to and from the charge air cooler for cracks or
loose clamps resulting in loss of pressure and
reduced engine performance.

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368SERVICING AND MAINTENANCE
Automatic Transmission
Selection Of Lubricant
It is important to use the proper transmission
fluid to ensure optimum transmission perfor-
mance and life. Use only the manufacturer’s
specified transmission fluid. Refer to “Fluids
And Lubricants” in “Technical Specifications”. It
is important to maintain the transmission fluid
at the correct level using the recommended
fluid. No chemical flushes should be used in any
transmission; only the approved lubricant
should be used.
Special Additives
The manufacturer strongly recommends
against using any special additives in the trans -
mission. Automatic Transmission Fluid (ATF) is
an engineered product and its performance
may be impaired by supplemental additives.
Therefore, do not add any fluid additives to the
transmission. The only exception to this policy is
the use of special dyes for diagnosing fluid
leaks in six-speed transmissions. Avoid using
transmission sealers as they may adversely
affect seals.
Fluid Level Check — Eight-Speed
Transmission
The fluid level is preset at the factory and does
not require adjustment under normal operating
conditions. Routine fluid level checks are not
required, therefore the transmission has no dipstick. An authorized dealer can check your
transmission fluid level using special service
tools.
If you notice fluid leakage or transmission
malfunction, visit an authorized dealer immedi
-
ately to have the transmission fluid level
checked. Operating the vehicle with an
improper fluid level can cause severe transmis -
sion damage.
Fluid Level Check — Six-Speed Transmission
It is best to check the fluid level when the trans -
mission is at normal operating temperature
(158-176°F / 70-80°C). This normally occurs
after at least 15 miles (25 km) of driving. At
normal operating temperature the fluid cannot
be held comfortably between the fingertips. You
can read the transmission sump temperature in
the instrument cluster screen (refer to “Instru -
ment Cluster Display” in “Getting To Know Your
Instrument Panel” for further information).
CAUTION!
Using a transmission fluid other than the
manufacturer’s recommended fluid may
cause deterioration in transmission shift
quality and/or torque converter shudder, and
(for six-speed transmissions) will require
more frequent fluid and filter changes. Refer
to “Fluids And Lubricants” in “Technical
Specifications” for fluid specifications.
CAUTION!
Do not use chemical flushes in your
transmission as the chemicals can damage
your transmission components. Such damage
is not covered by the New Vehicle Limited
Warranty.
CAUTION!
If a transmission fluid leak occurs, visit an
authorized dealer immediately. Severe
transmission damage may occur. An
authorized dealer has the proper tools to
adjust the fluid level accurately.

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372SERVICING AND MAINTENANCE
Exhaust System
Inspect the entire exhaust system for leaks and
damaged parts. Devices such as hangers,
clamps, and U-bolts should be tight and in good
condition. Damaged components, burned or
blown out mufflers, burned or rusted out
exhaust pipes should be replaced according to
the procedures and specifications outlined in
the appropriate service manual.
Air Cleaner Assembly
Inspect air cleaner housing for proper assembly
and fit. Make certain that the air cleaner is prop -
erly positioned and that the cover is tight. Check
all hoses leading to the air cleaner for tightness.
The air filter element must also be clean and
serviced according to the instructions outlined
in the Scheduled Maintenance section of this
manual.Tampering With Noise Control System
Prohibited
Federal law prohibits the following acts or the
causing thereof: (1) the removal or rendering
inoperative by any person, other than for
purposes of maintenance, repair, or replace -
ment, of any device or element of design incor -
porated into any new vehicle for the purpose of
noise control prior to its sale or delivery to the
ultimate purchaser or while it is in use, or (2) the
use of the vehicle after such device or element
of design has been removed or rendered inop -
erative by any person.
Among those acts presumed to constitute
tampering are the acts listed below.
AIR CLEANER
Removal of the air cleaner.
Removal of the air cleaner filter element from
the air cleaner housing.
Removal of the air ducting.
EXHAUST SYSTEM
Removal or rendering inoperative exhaust
system components including the muffler or
tailpipe. ENGINE COOLING SYSTEM

Removal or rendering inoperative the fan
clutch.
Removal of the fan shroud.
Noise Emission Warranty
The manufacturer warrants that this vehicle as
manufactured by the manufacturer, was
designed, built and equipped to conform at the
time it left the manufacturer's control with all
applicable U.S. EPA Noise Control Regulations.
This warranty covers this vehicle as designed,
built and equipped by the manufacturer, and is
not limited to any particular part, component or
system of the vehicle manufactured by the
manufacturer. Defects in design, assembly or in
any part, component or system of the vehicle as
manufactured by the manufacturer, which, at
the time it left the manufacturer's control,
caused noise emissions to exceed Federal stan -
dards, are covered by this warranty for the life of
the vehicle.

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SERVICING AND MAINTENANCE383
Tire Inflation Pressures
The proper cold tire inflation pressure is listed
on the driver's side B-Pillar or rear edge of the
driver's side door.
At least once a month:
Check and adjust tire pressure with a good
quality pocket-type pressure gauge. Do not
make a visual judgement when determining
proper inflation. Tires may look properly
inflated even when they are under-inflated.
Inspect tires for signs of tire wear or visible
damage.
Inflation pressures specified on the placard are
always “cold tire inflation pressure”. Cold tire
inflation pressure is defined as the tire pressure
after the vehicle has not been driven for at least
three hours, or driven less than 1 mile (1.6 km) after sitting for a minimum of three hours. The
cold tire inflation pressure must not exceed the
maximum inflation pressure molded into the
tire sidewall.
Check tire pressures more often if subject to a
wide range of outdoor temperatures, as tire
pressures vary with temperature changes.
Tire pressures change by approximately 1 psi
(7 kPa) per 12°F (7°C) of air temperature
change. Keep this in mind when checking tire
pressure inside a garage, especially in the
Winter.
Example: If garage temperature = 68°F (20°C)
and the outside temperature = 32°F (0°C) then
the cold tire inflation pressure should be
increased by 3 psi (21 kPa), which equals 1 psi
(7 kPa) for every 12°F (7°C) for this outside
temperature condition.
Tire pressure may increase from 2 to 6 psi
(13 to 40 kPa) during operation. DO NOT reduce
this normal pressure build up or your tire pres
-
sure will be too low.
Tire Pressures For High Speed Operation
The manufacturer advocates driving at safe
speeds and within posted speed limits. Where
speed limits or conditions are such that the
vehicle can be driven at high speeds, main -
taining correct tire inflation pressure is very
important. Increased tire pressure and reduced
vehicle loading may be required for high-speed
vehicle operation. Refer to an authorized tire
dealer or original equipment vehicle dealer for
recommended safe operating speeds, loading
and cold tire inflation pressures.
CAUTION!
After inspecting or adjusting the tire pressure,
always reinstall the valve stem cap. This will
prevent moisture and dirt from entering the
valve stem, which could damage the valve
stem.
WARNING!
High speed driving with your vehicle under
maximum load is dangerous. The added
strain on your tires could cause them to fail.
You could have a serious collision. Do not
drive a vehicle loaded to the maximum
capacity at continuous speeds above 75 mph
(120 km/h).
7

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384SERVICING AND MAINTENANCE
Radial Ply Tires
Tire Repair
If your tire becomes damaged, it may be
repaired if it meets the following criteria:
The tire has not been driven on when flat.
The damage is only on the tread section of
your tire (sidewall damage is not repairable).
The puncture is no greater than a ¼ of an
inch (6 mm).
Consult an authorized tire dealer for tire repairs
and additional information. Damaged Run Flat tires, or Run Flat tires that
have experienced a loss of pressure should be
replaced immediately with another Run Flat tire
of identical size and service description (Load
Index and Speed Symbol). Replace the tire pres
-
sure sensor as well as it is not designed to be
reused.
Run Flat Tires — If Equipped
Run Flat tires allow you the capability to drive
50 miles (80 km) at 50 mph (80 km/h) after a
rapid loss of inflation pressure. This rapid loss
of inflation is referred to as the Run Flat mode.
A Run Flat mode occurs when the tire inflation
pressure is of/or below 14 psi (96 kPa). Once a
Run Flat tire reaches the run flat mode it has
limited driving capabilities and needs to be
replaced immediately. A Run Flat tire is not
repairable. When a run flat tire is changed after
driving with underinflated tire condition, please
replace the TPM sensor as it is not designed to
be reused when driven under run flat mode
14 psi (96 kPa) condition. NOTE:
TPM Sensor must be replaced after driving the
vehicle on a flat tire condition.
It is not recommended driving a vehicle loaded
at full capacity or to tow a trailer while a tire is in
the run flat mode.
See the tire pressure monitoring section for
more information.Tire Spinning
When stuck in mud, sand, snow, or ice condi
-
tions, do not spin your vehicle's wheels above
30 mph (48 km/h) or for longer than 30
seconds continuously without stopping.
Refer to “Freeing A Stuck Vehicle” in “In Case Of
Emergency” for further information.
WARNING!
Combining radial ply tires with other types of
tires on your vehicle will cause your vehicle to
handle poorly. The instability could cause a
collision. Always use radial ply tires in sets of
four. Never combine them with other types of
tires.
WARNING!
Fast spinning tires can be dangerous. Forces
generated by excessive wheel speeds may
cause tire damage or failure. A tire could
explode and injure someone. Do not spin your
vehicle's wheels faster than 30 mph
(48 km/h) for more than 30 seconds
continuously when you are stuck, and do not
let anyone near a spinning wheel, no matter
what the speed.

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