ECU Ram 4500 Chassis Cab 2019 Service Manual

STARTING AND OPERATING 339
rear to front as appropriate until the specified weight limita-
tions are met. Store the heavier items down low and be sure
that the weight is distributed equally. Stow all loose items
securely before driving.
Improper weight distributions can have an adverse effect on
the way your vehicle steers and handles and the way the
brakes operate.
TRAILER TOWING
In this section you will find safety tips and information on
limits to the type of towing you can reasonably do with your
vehicle. Before towing a trailer, carefully review this infor -
mation to tow your load as efficiently and safely as possible.
To maintain the New Vehicle Limited Warranty coverage,
follow the requirements and recommendations in this
manual concerning vehicles used for trailer towing.
Common Towing Definitions
The following trailer towing related definitions will assist
you in understanding the following information:
Gross Vehicle Weight Rating (GVWR)
The GVWR is the total allowable weight of your vehicle. This
includes driver, passengers, cargo and tongue weight. The
total load must be limited so that you do not exceed the
GVWR. Refer to “Vehicle Loading/Vehicle Certification
Label” in “Starting And Operating” for further information.
Gross Trailer Weight (GTW)
The GTW is the weight of the trailer plus the weight of all
cargo, consumables and equipment (permanent or tempo -
rary) loaded in or on the trailer in its "loaded and ready for
operation" condition.
The recommended way to measure GTW is to put your fully
loaded trailer on a vehicle scale. The entire weight of the
trailer must be supported by the scale.
CAUTION!
Do not load your vehicle any heavier than the GVWR or
the maximum front and rear GAWR. If you do, parts on
your vehicle can break, or it can change the way your
vehicle handles. This could cause you to lose control.
Also overloading can shorten the life of your vehicle.
5

STARTING AND OPERATING 347
(Continued)
Towing Requirements — Tires
• Do not attempt to tow a trailer while using a compact sparetire.
• Do not drive more than 50 mph (80 km/h) when towing while using a full size spare tire.
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. Overloading 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)
5

STARTING AND OPERATING 359
(Continued)
Recreational Towing — Two-Wheel Drive Models
DO NOT flat tow this vehicle. Damage to the drivetrain
will result.
Recreational towing (for two-wheel drive models) is allowed
ONLY if the rear 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 rear wheels onto the tow dolly.
3. Firmly apply the parking brake. Place automatic trans -
mission in PARK.
4. Properly secure the rear wheels to the dolly, following the dolly manufacturer's instructions.
5. Turn the ignition OFF and remove the key fob.
6. Install a suitable clamping device, designed for towing, to secure the front wheels in the straight position.
Recreational Towing — Four-Wheel Drive Models
NOTE:
Both the manual shift and electronic shift transfer cases must
be shifted into NEUTRAL (N) for recreational towing. Auto -
matic transmissions must be shifted into PARK for recre -
ational towing. Refer to the following for the proper transfer
case NEUTRAL (N) shifting procedure for your vehicle. CAUTION!
• Towing with the rear wheels on the ground will cause severe transmission damage. Damage from improper
towing is not covered under the New Vehicle Limited
Warranty.
• Do not disconnect the driveshaft because fluid may leak from the transmission, causing damage to internal
parts.
CAUTION!
• DO NOT dolly tow any 4WD vehicle. Towing with only one set of wheels on the ground (front or rear) will
cause severe transmission and/or transfer case damage.
Tow with all four wheels either ON the ground, or OFF
the ground (using a vehicle trailer).5

382 IN CASE OF EMERGENCY
F0820 Amp Blue (DS 1500
LD/Cummins Diesel) 40 Amp Green –
–
NOX Sensor – If Equipped
Aux Relay Output- SSV Only
F09 40 Amp Green (SSV &
Cummins Diesel) –
Aux Relay Output / Diesel Fuel Heater – If Equipped
F09 30 Amp Pink –Brake Vacuum Pump – If Equipped (HD Only)
F10 40 Amp Green –Body Controller / Exterior Lighting #2
F11 30 Amp Pink –PWR - Trailer Tow Electric Brake Batt Feed – If
Equipped (DS 1500 Only)
F11 40 Amp Green –Brake System Module (ECU and Valves) (HD Only)
F12 40 Amp Green –Body Controller #3
F13 40 Amp Green –Blower Motor
F14 40 Amp Green –Body Controller #4 / Exterior Lighting
F15 30 Amp Pink
40 Amp Green –
–Power Side Steps – If Equipped (HD Only)
Extra Fuse - SSV Only
F16 30 Amp Pink –Smart-Bar Module – If Equipped (HD Only)
F17 30 Amp Pink –Winch Control Module – If Equipped (HD Only)
F19 20 Amp Blue (DS 1500
LD Diesel)
30 Amp Pink
(Cummins Diesel) –
SCR – If Equipped
Cavity Cartridge Fuse
Micro FuseDescription

IN CASE OF EMERGENCY 393
Jack Warning Label1. If equipped, remove the spare wheel, jack, and tools from
storage.
2. Using the lug wrench, loosen, but do not remove, the lug nuts by turning them counterclockwise one turn while
the wheel is still on the ground.
• To assure that spare tires, flat or inflated, are securely
stowed, spares must be stowed with the valve stem
facing the ground.
WARNING! (Continued)CAUTION!
Do not attempt to raise the vehicle by jacking on
locations other than those indicated in the Jacking
Instructions for this vehicle.
6

394 IN CASE OF EMERGENCY
3. When changing the front wheel, assemble the jack driverto the jack and connect the jack driver to the extension
tube. Place the jack under the axle as close to the tire as
possible with the jack driver extending to the front.
Connect the extension tubes and lug wrench.
Front Jacking Locations
When changing a rear wheel, assemble the jack driver to
the jack and connect the jack driver to the extension tubes.
Securely place the jack under the sway bar bracket (unless
both tires are flat on one side, then place jack under shock
bracket) facing forward in vehicle. Connect the extension
tubes and lug wrench. Rear Jacking Location
Before raising the wheel off the ground, make sure that
the jack will not damage surrounding truck parts and
adjust the jack position as required.
NOTE:
If the jack will not lower by turning the dial (thumbwheel) by
hand, it may be necessary to use the jack driver in order to
lower the jack.
4. By rotating the lug wrench clockwise, raise the vehicle until the wheel just clears the surface.

IN CASE OF EMERGENCY 403
Gear Selector Override Access Port
6. Move the gear selector to the NEUTRAL position.
7. The vehicle may then be started in NEUTRAL.
MANUAL PARK RELEASE — 8–SPEED
TRANSMISSION
In order to push or tow the vehicle in cases where the trans -
mission will not shift out of PARK (P) (such as a dead
battery), a Manual Park Release is available.
WARNING!
Always secure your vehicle by fully applying the
parking brake before activating the Manual Park
Release. In addition, you should be seated in the driver’s
seat with your foot firmly on the brake pedal when
activating the Manual Park Release. Activating the
Manual Park Release will allow your vehicle to roll away
if it is not secured by the parking brake, or by proper
connection to a tow vehicle. Activating the Manual Park
Release on an unsecured vehicle could lead to serious
injury or death for those in or around the vehicle.
6

404 IN CASE OF EMERGENCY
Manual Park Release Pull Strap
Follow these steps to activate the Manual Park Release:
1. Firmly apply the parking brake.
2. Using a small screwdriver or similar tool, remove the Manual Park Release access cover, which is just above the
parking brake release handle, below and to the left of the
steering column.
3. Press and maintain firm pressure on the brake pedal. 4. Using the screwdriver or similar tool, push the Manual
Park Release lever locking tab (just below the middle of
the lever) to the right.
5. While holding the locking tab in the disengaged position, pull the tether strap to rotate the lever rearward, until it
locks in place pointing towards the driver's seat. Release
the locking tab and verify that the Manual Park Release
lever is locked in the released position.
6. The vehicle is now out of PARK (P) and can be towed. Release the parking brake only when the vehicle is
securely connected to a tow vehicle.
To Reset The Manual Park Release:
1. Push the locking tab to the right, to unlock the lever.
2. Rotate the Manual Park Release lever forward to its orig -
inal position, until the locking tab snaps into place to
secure the lever.
3. Pull gently on the tether strap to confirm that the lever is locked in its stowed position.
4. Re-install the access cover.

IN CASE OF EMERGENCY 407
Proper towing or lifting equipment is required to prevent
damage to your vehicle. Use only tow bars and other equip-
ment designed for this purpose, following equipment manu-
facturer’s instructions. Use of safety chains is mandatory.
Attach a tow bar or other towing device to main structural
members of the vehicle, not to bumpers or associated
brackets. State and local laws regarding vehicles under tow
must be observed.
If you must use the accessories (wipers, defrosters, etc.)
while being towed, the ignition must be in the ON/RUN
mode, not the ACC mode.
If the key fob is unavailable or the vehicle's battery is
discharged, refer to “Manual Park Release” or “Gear Selector
Override” in this section for instructions on shifting the auto -
matic transmission out of PARK for towing.Two-Wheel Drive Models
The manufacturer recommends towing your vehicle with all
four wheels OFF the ground using a flatbed.
If flatbed equipment is not available, and the transmission is
operable, the vehicle may be towed (with the rear wheels on
the ground) under the following conditions:
• The transmission must be in NEUTRAL. Refer to “Manual Park Release” in this section for instructions on shifting the
8–speed transmission to NEUTRAL when the engine is off.
• The towing speed must not exceed 30 mph (48 km/h).
• The towing distance must not exceed 15 miles (24 km) for 6–speed transmission, or 30 miles (48 km) for 8–speed
transmission.
If the transmission is not operable, or the vehicle must be
towed faster than 30 mph (48 km/h) or farther than 15 miles (24 km) for 6–speed transmission, or 30 miles (48 km) for
8–speed transmission, tow with the rear wheels OFF the
ground. Acceptable methods are to tow the vehicle on a
flatbed, or with the front wheels raised and the rear wheels
on a towing dolly, or (when using a suitable steering wheel
stabilizer to hold the front wheels in the straight position)
with rear wheels raised and the front wheels on the ground.
CAUTION!
• Do not use sling type equipment when towing. Vehicle damage may occur.
• When securing the vehicle to a flat bed truck, do not attach to front or rear suspension components. Damage
to your vehicle may result from improper towing.
6

438 SERVICING AND MAINTENANCE
(Continued)
Brake System
In order to assure brake system performance, all brake
system components should be inspected periodically. Refer
to the “Maintenance Plan” in this section for the proper
maintenance intervals.
Fluid Level Check — Brake Master Cylinder
The fluid level of the master cylinder should be checked
when performing under the hood service or immediately if
the brake system warning lamp indicates system failure.
If necessary, add fluid to bring level within the designated
marks on the side of the reservoir of the brake master
cylinder. Be sure to clean the top of the master cylinder area
before removing cap.With disc brakes the fluid level can be expected to fall as the
brake linings wear. However, an unexpected drop in fluid
level may be caused by a leak and a system check should be
conducted.
Refer to “Fluids And Lubricants” in “Technical Specifica
-
tions” for further information.
WARNING!
Riding the brakes can lead to brake failure and possibly
a collision. Driving with your foot resting or riding on
the brake pedal can result in abnormally high brake
temperatures, excessive lining wear, and possible brake
damage. You would not have your full braking capacity
in an emergency.
WARNING!
• Use only manufacturer's recommended brake fluid. Refer to “Fluids And Lubricants” in “Technical Speci -
fications” for further information. Using the wrong
type of brake fluid can severely damage your brake
system and/or impair its performance. The proper type
of brake fluid for your vehicle is also identified on the
original factory installed hydraulic master cylinder
reservoir.
• To avoid contamination from foreign matter or mois -
ture, use only new brake fluid or fluid that has been in
a tightly closed container. Keep the master cylinder
reservoir cap secured at all times. Brake fluid in a open
container absorbs moisture from the air resulting in a
lower boiling point. This may cause it to boil unexpect -
edly during hard or prolonged braking, resulting in
sudden brake failure. This could result in a collision.