2002 DODGE RAM Cooling system

CONDITION POSSIBLE CAUSES CORRECTION
BUZZING NOISE 1. Fluid Level Low 1. Add fluid and check for leaks.
2. Shift Cable Mis-assembled. 2. Route cable away from engine and bell
housing.
3. Valve Body Mis-assembled. 3. Remove, disassemble, inspect valve
body. Reassemble correctly if necessary.
Replace assembly if valves or springs are
damaged. Check for loose bolts or screws.
4. Pump Passages Leaking. 4. Check pump for porous casting, scores
on mating surfaces and excess rotor
clearance. Repair as required. Loose pump
bolts.
5. Cooling System Cooler Plugged. 5. Flow check cooler circuit. Repair as
needed.
6. Overrunning Clutch Damaged. 6. Replace clutch.
SLIPS IN REVERSE ONLY 1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Gearshift Linkage Mis-adjusted. 2. Adjust linkage.
3. Rear Band Mis-adjusted. 3. Adjust band.
4. Rear Band Worn. 4. Replace as required.
5. Overdrive Direct Clutch Worn. 5. Disassemble overdrive. Repair as
needed.
6. Hydraulic Pressure Too Low. 6. Perform hydraulic pressure tests to
determine cause.
7. Rear Servo Leaking. 7. Air pressure check clutch-servo operation
and repair as required.
8. Band Linkage Binding. 8. Inspect and repair as required.
SLIPS IN FORWARD
DRIVE RANGES1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Fluid Foaming. 2. Check for high oil level, bad pump
gasket or seals, dirt between pump halves
and loose pump bolts. Replace pump if
necessary.
3. Throttle Linkage Mis-adjusted. 3. Adjust linkage.
4. Gearshift Linkage Mis-adjusted. 4. Adjust linkage.
5. Rear Clutch Worn. 5. Inspect and replace as needed.
6. Low Hydraulic Pressure Due to
Worn Pump, Incorrect Control
Pressure Adjustments, Valve Body
Warpage or Malfunction, Sticking,
Leaking Seal Rings, Clutch Seals
Leaking, Servo Leaks, Clogged Filter
or Cooler Lines.6. Perform hydraulic and air pressure tests
to determine cause.
7. Rear Clutch Malfunction, Leaking
Seals or Worn Plates.7. Air pressure check clutch-servo operation
and repair as required.
8. Overrunning Clutch Worn, Not
Holding (Slips in 1 Only).8. Replace Clutch.
BR/BEAUTOMATIC TRANSMISSION - 46RE 21 - 107
AUTOMATIC TRANSMISSION - 46RE (Continued)

FLUID AND FILTER
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air
along with the fluid. Air in the fluid will cause fluid
pressures to be low and develop slower than normal.
If the transmission is overfilled, the gears churn the
fluid into foam. This aerates the fluid and causing
the same conditions occurring with a low level. In
either case, air bubbles cause fluid overheating, oxi-
dation and varnish buildup which interferes with
valve and clutch operation. Foaming also causes fluid
expansion which can result in fluid overflow from the
transmission vent or fill tube. Fluid overflow can eas-
ily be mistaken for a leak if inspection is not careful.
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID
Burnt, discolored fluid is a result of overheating
which has two primary causes.
(1) A result of restricted fluid flow through the
main and/or auxiliary cooler. This condition is usu-
ally the result of a faulty or improperly installed
drainback valve, a damaged main cooler, or severe
restrictions in the coolers and lines caused by debris
or kinked lines.
(2) Heavy duty operation with a vehicle not prop-
erly equipped for this type of operation. Trailer tow-
ing or similar high load operation will overheat the
transmission fluid if the vehicle is improperly
equipped. Such vehicles should have an auxiliary
transmission fluid cooler, a heavy duty cooling sys-
tem, and the engine/axle ratio combination needed to
handle heavy loads.
DIAGNOSIS AND TESTING - FLUID
CONTAMINATION
Transmission fluid contamination is generally a
result of:
²adding incorrect fluid
²failure to clean dipstick and fill tube when
checking level
²engine coolant entering the fluid
²internal failure that generates debris
²overheat that generates sludge (fluid break-
down)
²failure to reverse flush cooler and lines after
repair
²failure to replace contaminated converter after
repair
The use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failure
due to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped
clean before checking fluid level. Dirt, grease and
other foreign material on the cap and tube could fall
into the tube if not removed beforehand. Take the
time to wipe the cap and tube clean before withdraw-
ing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The transmission cooler and lines should be
reverse flushed whenever a malfunction generates
sludge and/or debris. The torque converter should
also be replaced at the same time.
Failure to flush the cooler and lines will result in
recontamination. Flushing applies to auxiliary coolers
as well. The torque converter should also be replaced
whenever a failure generates sludge and debris. This is
necessary because normal converter flushing procedures
will not remove all contaminants.
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transmssion has too much fluid, the
geartrain churns up foam and cause the same condi-
tions which occur with a low fluid level.
Fig. 88 Installing Overdrive Housing Seal
1 - SPECIAL TOOL C-3995-A OR C-3972-A
2 - SPECIAL TOOL C-4471
BR/BEAUTOMATIC TRANSMISSION - 46RE 21 - 157
EXTENSION HOUSING SEAL (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
BUZZING NOISE 1. Fluid Level Low 1. Add fluid and check for leaks.
2. Shift Cable Mis-assembled. 2. Route cable away from engine and bell
housing.
3. Valve Body Mis-assembled. 3. Remove, disassemble, inspect valve
body. Reassemble correctly if necessary.
Replace assembly if valves or springs are
damaged. Check for loose bolts or screws.
4. Pump Passages Leaking. 4. Check pump for porous casting, scores
on mating surfaces and excess rotor
clearance. Repair as required. Loose pump
bolts.
5. Cooling System Cooler Plugged. 5. Flow check cooler circuit. Repair as
needed.
6. Overrunning Clutch Damaged. 6. Replace clutch.
SLIPS IN REVERSE ONLY 1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Gearshift Linkage Mis-adjusted. 2. Adjust linkage.
3. Rear Band Mis-adjusted. 3. Adjust band.
4. Rear Band Worn. 4. Replace as required.
5. Overdrive Direct Clutch Worn. 5. Disassemble overdrive. Repair as
needed.
6. Hydraulic Pressure Too Low. 6. Perform hydraulic pressure tests to
determine cause.
7. Rear Servo Leaking. 7. Air pressure check clutch-servo operation
and repair as required.
8. Band Linkage Binding. 8. Inspect and repair as required.
SLIPS IN FORWARD
DRIVE RANGES1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Fluid Foaming. 2. Check for high oil level, bad pump
gasket or seals, dirt between pump halves
and loose pump bolts. Replace pump if
necessary.
3. Throttle Linkage Mis-adjusted. 3. Adjust linkage.
4. Gearshift Linkage Mis-adjusted. 4. Adjust linkage.
5. Rear Clutch Worn. 5. Inspect and replace as needed.
6. Low Hydraulic Pressure Due to
Worn Pump, Incorrect Control
Pressure Adjustments, Valve Body
Warpage or Malfunction, Sticking,
Leaking Seal Rings, Clutch Seals
Leaking, Servo Leaks, Clogged Filter
or Cooler Lines.6. Perform hydraulic and air pressure tests
to determine cause.
7. Rear Clutch Malfunction, Leaking
Seals or Worn Plates.7. Air pressure check clutch-servo operation
and repair as required.
8. Overrunning Clutch Worn, Not
Holding (Slips in 1 Only).8. Replace Clutch.
SLIPS IN LOW GEAR9D9
ONLY, BUT NOT IN
MANUAL 1 POSITIONOverrunning Clutch Faulty. Replace overrunning clutch.
BR/BEAUTOMATIC TRANSMISSION - 47RE 21 - 279
AUTOMATIC TRANSMISSION - 47RE (Continued)

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION...........................1
OPERATION.............................1
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE........................2
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE........................6STANDARD PROCEDURE
STANDARD PROCEDURE - DIODE
REPLACEMENT.........................7
SPECIFICATIONS.........................7
CONTROLS.............................9
DISTRIBUTION..........................30
PLUMBING.............................40
HEATING & AIR
CONDITIONING
DESCRIPTION - HEATER AND AIR
CONDITIONER
All vehicles are equipped with a common HVAC
housing assembly (Fig. 1). The system combines air
conditioning, heating, and ventilating capabilities in
a single unit housing mounted under the instrument
panel. On heater-only systems, the evaporator coil
and recirculation door are omitted from the housing.
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS
To maintain the performance level of the HVAC
system, the engine cooling system must be properly
maintained. The use of a bug screen is not recom-
mended. Any obstructions in front of the radiator orcondenser will reduce the performance of the air con-
ditioning and engine cooling systems.
The engine cooling system includes the heater core
and the heater hoses. Refer to Engine Cooling for
more information before the opening of, or attempt-
ing any service to the engine cooling system.
DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT
The two refrigerant system service ports are used
to charge, recover/recycle, evacuate, and test the air
conditioning refrigerant system. Unique service port
coupler sizes are used on the R-134a system, to
ensure that the refrigerant system is not accidentally
contaminated by the use of the wrong refrigerant
(R-12), or refrigerant system service equipment.
OPERATION - HEATER AND AIR CONDITIONER
The heater and optional air conditioner are blend-
air type systems. In a blend-air system, a blend door
controls the amount of unconditioned air (or cooled
air from the evaporator on models with air condition-
ing) that is allowed to flow through, or around, the
heater core. A temperature control knob on the A/C
Heater control panel determines the discharge air
temperature by controlling an electric actuator,
which moves the blend door. This allows an almost
immediate control of the output air temperature of
the system.
The mode control knob on the heater-only or A/C
Heater control panel is used to direct the conditioned
air to the selected system outlets. Both mode control
switches use engine vacuum to control the mode
doors, which are operated by vacuum actuators.
On air conditioned vehicles, the outside air intake
can be shut off by selecting the Recirculation Mode
with the mode control knob. This will operate a vac-
uum actuated recirculation door that closes off the
outside fresh air intake and recirculates the air that
is already inside the vehicle.
Fig. 1 COMMON BLEND-AIR HEATER-AIR
1 - HEATER CORE
2 - BLEND DOOR
3 - EVAPORATOR (A/C ONLY)
4 - RECIRCULATION DOOR (A/C ONLY)
5 - FLOOR/PANEL DOOR
6 - FLOOR/DEFROST DOOR
BR/BEHEATING & AIR CONDITIONING 24 - 1

A/C Diagnosis
Condition Possible Causes Correction
2. Refrigerant flow
through the accumulator
is restricted.2. (Refer to Plumbing/Accumulator/ Removal/Installation)
in this group. Replace the restricted accumulator, if
required.
3. Refrigerant flow
through the a/c
evaporator is restricted.3. (Refer to Plumbing/A/C Evaporator/ Removal/
Installation) in this group. Replace the restricted
evaporator, if required.
4. Faulty compressor. 4. (Refer to Plumbing/A/C Compressor/ Removal/
Installation) in this group. Replace the compressor, if
required.
LOW SIDE PRESSURE
IS NORMAL OR
SLIGHTLY HIGH, AND
HIGH SIDE PRESSURE
IS TOO HIGH.1. Condenser air flow
restricted.1. Check the condenser for damaged fins, foreign objects
obstructing air flow through the condenser fins, and
missing or improperly installed air seals. Refer to Cooling
for more information on air seals. Clean, repair, or replace
components as required.
2. Inoperative cooling
fan.2. Refer to Cooling for more information. Test the cooling
fan and replace, if required.
3. Refrigerant system
overcharged.3. (Refer to Plumbing/Standard Procedure - Refrigerant
System Charge) in this group. Recover the refrigerant
from the refrigerant system. Charge the refrigerant
system to the proper level, if required.
4. Air in the refrigerant
system.4. (Refer to Plumbing/Diagnosis and Testing - Refrigerant
System Leaks) in this group. Test the refrigerant system
for leaks. Repair, evacuate and charge the refrigerant
system, if required.
5. Engine overheating. 5. Refer to Cooling for more information. Test the cooling
system and repair, if required.
LOW SIDE PRESSURE
IS TOO HIGH, AND
HIGH SIDE PRESSURE
IS TOO LOW.1. Accessory drive belt
slipping.1. Refer to Cooling for more information. Inspect the
accessory drive belt condition and tension. Tighten or
replace the accessory drive belt, if required.
2. A/C orifice tube not
installed.2. (Refer to Plumbing/A/C Orifice Tube/Diagnosis and
Testing) in this group. Replace the liquid line, if required.
3. Faulty a/c compressor. 3. (Refer to Plumbing/A/C Compressor/ Removal/
Installation) in this group. Replace the compressor, if
required.
LOW SIDE PRESSURE
IS TOO LOW, AND HIGH
SIDE PRESSURE IS
TOO HIGH.1. Restricted refrigerant
flow through the
refrigerant lines.1. (Refer to Plumbing/Caution - Refrigerant Hoses/Lines/
Tubes Precautions) in this group. Inspect the refrigerant
lines for kinks, tight bends or improper routing. Correct
the routing or replace the refrigerant line, if required.
2. Restricted refrigerant
flow through the a/c
orifice tube.2. (Refer to Plumbing/A/C Orifice Tube/Diagnosis and
Testing) in this group. Replace the liquid line, if required.
3. Restricted refrigerant
flow through the a/c
condenser.3. (Refer to Plumbing/A/C Condenser/ Removal/
Installation) in this group. Replace the restricted a/c
condenser, if required.
BR/BEHEATING & AIR CONDITIONING 24 - 5
HEATING & AIR CONDITIONING (Continued)

DIAGNOSIS AND TESTING - HEATER
PERFORMANCE
Before performing the following tests, refer to Cool-
ing for the procedures to check the engine coolant
level and flow, engine coolant reserve/recovery sys-
tem operation, accessory drive belt condition and ten-
sion, radiator air flow and the fan drive operation.
Also be certain that the accessory vacuum supply
line is connected at the engine vacuum source.
MAXIMUM HEATER OUTPUT
Engine coolant is delivered to the heater core
through two heater hoses. With the engine idling atnormal operating temperature, set the temperature
control knob in the full hot position, the mode control
switch knob in the floor position, and the blower
motor switch knob in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged at the HVAC housing floor
outlets. Compare the test thermometer reading to the
Temperature Reference chart.
Temperature Reference
Ambient Air Temperature15.5É C
(60É F)21.1É C
(70É F)26.6É C
(80É F)32.2É C
(90É F)
Minimum Air Temperature at
Floor Outlet62.2É C
(144É F)63.8É C
(147É F)65.5É C
(150É F)67.2É C
(153É F)
If the floor outlet air temperature is too low, refer
to Cooling to check the engine coolant temperature
specifications. Both of the heater hoses should be hot
to the touch. The coolant return heater hose should
be slightly cooler than the coolant supply heater
hose. If the return hose is much cooler than the sup-
ply hose, locate and repair the engine coolant flow
obstruction in the cooling system. Refer to Cooling
for the procedures.
An alternate method of checking heater perfor-
mance is to use a DRBIIItscan tool to monitor the
engine coolant temperature. The floor outlet air tem-
perature reading should be no more than 4.5É C (40É
F) lower than the engine coolant temperature read-
ing.
OBSTRUCTED COOLANT FLOW Possible loca-
tions or causes of obstructed coolant flow:
²Faulty water pump.
²Faulty thermostat.
²Pinched or kinked heater hoses.
²Improper heater hose routing.
²Plugged heater hoses or supply and return ports
at the cooling system connections.
²A plugged heater core.If proper coolant flow through the cooling system is
verified, and heater outlet air temperature is still
low, a mechanical problem may exist.
MECHANICAL PROBLEMS Possible locations or
causes of insufficient heat:
²An obstructed cowl air intake.
²Obstructed heater system outlets.
²A faulty, obstructed or improperly installed
blend door.
²A faulty blower system.
²A faulty a/c heater control.
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
a/c heater control panel, the following could require
service:
²A faulty a/c heater control.
²A faulty blend door actuator.
²A faulty, obstructed or improperly installed
blend door.
²An obstructed cowl air intake.
²The engine cooling system.
Heater Diagnosis
CONDITION POSSIBLE CAUSE CORRECTION
INSUFFICIENT HEATER
OUTPUT.1. Incorrect engine
coolant level.1. Check the engine coolant level. Refer to Cooling for
the procedures.
2. Air trapped in engine
cooling system.2. Check the operation of the coolant reserve/recovery
system. Refer to Cooling for the procedures.
24 - 6 HEATING & AIR CONDITIONINGBR/BE
HEATING & AIR CONDITIONING (Continued)

Heater Diagnosis
3. Incorrect engine
coolant temperature.3. Check the performance and operation of the engine
cooling system including: thermostat, water pump, fan
drive, accessory drive belt, coolant flow (plugged radiator
or heater core, plugged or kinked coolant hoses), air flow
(missing or improperly installed radiator air seals or fan
shroud). Refer to Cooling for the procedures.
4. Blend door actuator
inoperative or defective.4. (Refer to Controls/Blend Door Actuator) in this group.
5. Blend door not
operating properly.5. Check for a damaged, obstructed or improperly
installed blend door or seals. (Refer to Controls/Blend
Door Actuator) in this group.
6. Insufficient air flow
through heater housing.6. Remove foreign material or obstructions from cowl air
intake.
7. Improper blower motor
operation.7. (Refer to Distribution/Blower Motor/ Diagnosis and
Testing) in this group.
STANDARD PROCEDURE - DIODE
REPLACEMENT
(1) Disconnect the battery negative cable and iso-
late it.
(2) Locate the diode in the harness, and remove
the protective covering.
(3) Remove the diode from the harness, pay atten-
tion to the current flow direction (Fig. 3).
(4) Remove the insulation from the wires in the
harness. Only remove enough insulation to solder in
the new diode.
(5) Install the new diode in the harness, making
sure current flow is correct. If necessary refer to the
appropriate wiring diagram for current flow.
(6) Solder the connection together using rosin core
type solder only.Do not use acid core solder.(7) Tape the diode to the harness using electrical
tape making, sure the diode is completely sealed
from the elements.
(8) Re-connect the battery negative cable, and test
affected systems.
SPECIFICATIONS
A/C APPLICATION TABLE
Item Description Notes
Vehicle BR/BE - Ram
Pickup
System R134a w/orifice
tube
Compressor Sanden SD7H15 SP-20 PAG oil
Freeze±up
ControlA/C Low
Pressure Switchaccumulator
mounted
Low psi Control opens < 22-24
psi resets >
37-43 psi
High psi Control switch - opens >
450 - 490 psi,
resets < 270 -
330 psimounted on
discharge line,
near
compressor
A/C Heater
Control Headmanual type
Mode Door vacuum actuator
Blend Door electric actuator
Recirculation
Doorvacuum actuator
Fig. 3 DIODE IDENTIFICATION
1 - CURRENT FLOW
2 - BAND AROUND DIODE INDICATES CURRENT FLOW
3 - DIODE AS SHOWN IN THE DIAGRAMS
BR/BEHEATING & AIR CONDITIONING 24 - 7
HEATING & AIR CONDITIONING (Continued)

(1) The relay common feed terminal cavity (30) is
connected to fused battery feed. There should be bat-
tery voltage at the cavity for relay terminal 30 at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the fuse in the PDC as required.
(2) The relay normally closed terminal (87A) is not
used in this application. Go to Step 3.
(3) The relay normally open terminal cavity (87) is
connected to the compressor clutch coil. There should
be continuity between this cavity and the A/C com-
pressor clutch relay output circuit cavity of the com-
pressor clutch coil wire harness connector. If OK, go
to Step 4. If not OK, repair the open circuit as
required.
(4) The relay coil battery terminal (86) is con-
nected to the fused ignition switch output (run/start)
circuit. There should be battery voltage at the cavity
for relay terminal 86 with the ignition switch in the
On position. If OK, go to Step 5. If not OK, repair the
open circuit to the fuse in the junction block as
required.
(5) The coil ground terminal cavity (85) is switched
to ground through the Powertrain Control Module
(PCM). There should be continuity between this cav-
ity and the A/C compressor clutch relay control cir-
cuit cavity of the PCM wire harness connector C
(gray) at all times. If not OK, repair the open circuit
as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 17).
(3) Refer to the label on the PDC for compressor
clutch relay identification and location.(4) Unplug the compressor clutch relay from the
PDC and remove it.
INSTALLATION
(1) Install the compressor clutch relay by aligning
the relay terminals with the cavities in the PDC and
pushing the relay firmly into place.
(2) Install the PDC cover.
(3) Connect the battery negative cable.
(4) Test the relay operation.
A/C-HEATER CONTROL
DESCRIPTION
Both the heater-only and a/c heater systems use a
combination of electrical and vacuum controls. These
controls provide the vehicle operator with a number
of setting options to help control the climate and
comfort within the vehicle. Refer to the owner's man-
ual in the vehicle glove box for more information on
the features, use, and suggested operation of these
controls.
OPERATION
The heater-only or a/c heater control panel is
located to the right of the instrument cluster on the
instrument panel. The control panel contains a rota-
ry-type temperature control knob, a rotary-type mode
control switch knob, and a rotary-type blower motor
speed switch knob. On models with the optional
heated mirror system, a momentary push button
switch and indicator lamp are located near the bot-
tom of the a/c heater control panel. Refer to Heated
Mirrors for more information on this feature.
The heater-only or a/c heater control panel cannot
be repaired. If faulty or damaged, the entire unit
must be replaced. The control knobs and the illumi-
nation lamps are available for service replacement.
DIAGNOSIS AND TESTING - A/C HEATER
CONTROL
Satisfactory heater and air conditioner perfor-
mance depends upon proper operation and adjust-
ment of all operating controls and refrigeration
system components. For circuit descriptions and dia-
grams, (Refer to Appropriate Wiring Information).
These inspections, tests, and adjustments should be
used to locate the cause of a malfunction.
Operation must be tested as described in the fol-
lowing sequence:
(1) Inspect and adjust the serpentine drive bel-
t(Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE
BELTS - DIAGNOSIS AND TESTING).
(2) Start the engine and hold the idle speed at
1,300 rpm.
Fig. 17 POWER DISTRIBUTION CENTER
1 - COVER
2 - POWER DISTRIBUTION CENTER
24 - 18 CONTROLSBR/BE
A/C COMPRESSOR CLUTCH RELAY (Continued)