2003 DODGE RAM app

Fig. 93 TAPPING PLATES - SHORT CARGO BOX ONLY
DRBODY STRUCTURE 23 - 175
WELD LOCATIONS (Continued)

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION
DESCRIPTION - HEATER AND AIR
CONDITIONER........................1
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS.......................1
DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT........................1
OPERATION
OPERATION - HEATER AND AIR
CONDITIONER........................1
OPERATION - REFRIGERANT SYSTEM
SERVICE PORT........................2DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE.......................2
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE.......................5
STANDARD PROCEDURE - DIODE
REPLACEMENT.......................7
SPECIFICATIONS
A/C APPLICATION TABLE................7
SPECIFICATIONS......................8
CONTROLS.............................9
DISTRIBUTION..........................24
PLUMBING.............................31
HEATING & AIR
CONDITIONING
DESCRIPTION
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.
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 or
condenser 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, toensure that the refrigerant system is not accidentally
contaminated by the use of the wrong refrigerant
(R-12), or refrigerant system service equipment.
OPERATION
OPERATION - HEATER AND AIR CONDITIONER
The heater air conditioner are blend-air type sys-
tems. In a blend-air system, a blend door controls the
amount of unconditioned air (or cooled air from the
evaporator on models with air conditioning) 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 A/C Heater control
panel is used to direct the conditioned air to the
selected system outlets. Both mode control switches
use electric actuators to control the mode doors.
On all vehicles, the outside air intake can be shut
off by selecting the Recirculation Mode with the
mode control knob. This will operate a electric actu-
ated recirculation door that closes off the outside
fresh air intake and recirculates the air that is
already inside the vehicle.
The air conditioner for all models is designed for
the use of non-CFC, R-134a refrigerant. The air con-
ditioning system has an evaporator to cool and dehu-
midify the incoming air prior to blending it with the
heated air. This air conditioning system uses a fixed
orifice tube in the liquid line near the condenser out-
let tube to meter refrigerant flow to the evaporator
DRHEATING & AIR CONDITIONING 24 - 1

Pressure Diagnosis
Condition Possible Causes Correction
4. Faulty a/c compressor
clutch relay.4. See A/C Compressor Clutch Relay/Diagnosis
and Testing - Compressor Clutch Relay in this
group. Test the compressor clutch relay and relay
circuits. Repair the circuits or replace the relay, if
required.
5. Improperly installed or
faulty Fin Sensor.5. See Fin Sensor/Diagnosis and Testing in this
group. Reinstall or replace the Fin Sensor as
required.
6. Faulty a/c high pressure
transducer.6. See A/C High Pressure Transducer/Diagnosis
and Testing in this group. Test the a/c high
pressure transducer and replace, if required.
7. Faulty Powertrain Control
Module (PCM).7. (Refer to Appropriate Diagnostic Information).
Test the PCM and replace, if required.
Normal pressures, but A/C
Performance Test air
temperatures at center panel
outlet are too high.1. Excessive refrigerant oil in
system.1. See Refrigerant Oil/Standard Procedure -
Refrigerant Oil Level in this group. Recover the
refrigerant from the refrigerant system and
inspect the refrigerant oil content. Restore the
refrigerant oil to the proper level, if required.
2. Blend door inoperative or
sealing improperly.2. See Blend Door in this group. Inspect the
blend door for proper operation and sealing and
correct, if required.
3. Blend door actuator faulty
or inoperative.3. Perform blend door actuator diagnosis, replace
if faulty.
The low side pressure is
normal or slightly low, and
the high side pressure is too
low.1. Low refrigerant system
charge.1. See 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.
2. Refrigerant flow through
the accumulator is restricted.2. See Accumulator in this group. Replace the
restricted accumulator, if required.
3. Refrigerant flow through
the evaporator coil is
restricted.3. See A/C Evaporator in this group. Replace the
restricted evaporator coil, if required.
4. Faulty compressor. 4. See A/C Compressor in this group. Replace
the compressor, if required.
The low side pressure is
normal or slightly high, and
the 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. See 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.
24 - 4 HEATING & AIR CONDITIONINGDR
HEATING & AIR CONDITIONING (Continued)

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.
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.
24 - 6 HEATING & AIR CONDITIONINGDR
HEATING & AIR CONDITIONING (Continued)

STANDARD PROCEDURE - DIODE
REPLACEMENT
(1) Disconnect the battery negative cable and iso-
late it. If vehicle has a dual batterys remove both
negative cables.
(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. 2).
(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 connections 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(s), and
test affected systems.
SPECIFICATIONS
A/C APPLICATION TABLE
Item Description Notes
Vehicle DR- Ram Truck
System R134a w/ fixed
orifice tube
Compressor Saden SD-7 SP-15 PAG oil
Freeze±up
ControlA/C Fin Sensor Evaporator
mounted
High psi Control 475 psi A/C cut
outdischarge line
Control Head electronic Software -
J2190
Mode Door electric
Blend Door electric
Recirculation
Doorelectric
Blower Motor hardwired to
control headresistor block
Cooling Fan Viscous for
cooling with a
single speed
electric for A/C
for 3.7, 4.7 and
5.7L gas
engines.
Viscous for
both cooling
and A/C with
5.9L diesel
engine and
8.0L gas
engine.
Clutch Electro-
mechanical
Control relay PCM
Draw 2 - 3.7 amps @
12V  0.5V @ 70É F
Gap 0.0169- 0.0319
DRB IIIT
Reads TPS, RPM, A/C
switch test
Actuators clutch and fan
relay
Fig. 2 DIODE IDENTIFICATION
1 - CURRENT FLOW
2 - BAND AROUND DIODE INDICATES CURRENT FLOW
3 - DIODE AS SHOWN IN THE DIAGRAMS
DRHEATING & AIR CONDITIONING 24 - 7
HEATING & AIR CONDITIONING (Continued)

seconds. Refer to Electronic Control Modules for
more information on the JTEC controls.
DIAGNOSIS AND TESTING - A/C COMPRESSOR
CLUTCH COIL
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information). The battery must
be fully-charged before performing the following
tests. Refer to Battery for more information.
(1) Connect an ammeter (0 to 10 ampere scale) in
series with the clutch coil terminal. Use a voltmeter
(0 to 20 volt scale) with clip-type leads for measuring
the voltage across the battery and the compressor
clutch coil.
(2) With the A/C Heater mode control switch in
any A/C mode, and the blower motor switch in the
lowest speed position, start the engine and run it at
normal idle.
(3) The compressor clutch coil voltage should read
within 0.2 volts of the battery voltage. If there is
voltage at the clutch coil, but the reading is not
within 0.2 volts of the battery voltage, test the clutch
coil feed circuit for excessive voltage drop and repair
as required. If there is no voltage reading at the
clutch coil, use a DRB IIItscan tool and (Refer to
Appropriate Diagnostic Information) for testing of the
compressor clutch circuit and PCM control. The fol-
lowing components must be checked and repaired as
required before you can complete testing of the clutch
coil:
²Fuses in the junction block and the Power Dis-
tribution Center (PDC)
²A/C heater mode control switch
²Compressor clutch relay
²A/C high pressure transducer switch²JTEC
(4) The compressor clutch coil is acceptable if the
current draw measured at the clutch coil is 2.0 to 3.9
amperes with the electrical system voltage at 11.5 to
12.5 volts. This should only be checked with the work
area temperature at 21É C (70É F). If system voltage
is more than 12.5 volts, add electrical loads by turn-
ing on electrical accessories until the system voltage
drops below 12.5 volts.
(a) If the clutch coil current reading is four
amperes or more, the coil is shorted and should be
replaced.
(b) If the clutch coil current reading is zero, the
coil is open and should be replaced.
STANDARD PROCEDURE - A/C COMPRESSOR
CLUTCH BREAK-IN
After a new compressor clutch has been installed,
cycle the compressor clutch approximately twenty
times (five seconds on, then five seconds off). During
this procedure, set the A/C Heater control to the
Recirculation Mode, the blower motor switch in the
highest speed position, and the engine speed at 1500
to 2000 rpm. This procedure (burnishing) will seat
the opposing friction surfaces and provide a higher
compressor clutch torque capability.
REMOVAL
The refrigerant system can remain fully-charged
during compressor clutch, rotor, or coil replacement.
The compressor clutch can be serviced in the vehicle.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the serpentine drive belt(Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(3) Unplug the compressor clutch coil wire harness
connector.
(4) Remove the bolts that secure the compressor to
the mounting bracket.
(5) Remove the compressor from the mounting
bracket. Support the compressor in the engine com-
partment while servicing the clutch.
(6) Insert the two pins of the spanner wrench
(Special Tool C-4489 or equivalent) into the holes of
the clutch plate. Hold the clutch plate stationary and
remove the hex nut (Fig. 2).
(7) Remove the clutch plate.
(8) Remove the compressor clutch shims.
(9) Remove the external front housing snap ring
with snap ring pliers (Fig. 3).
(10)
Install the lip of the rotor puller (Special Tool
C-6141-1 or equivalent) into the snap ring groove
exposed in the previous step, and install the shaft pro-
tector (Special Tool C-6141-2 or equivalent) (Fig. 4).
Fig. 1 COMPRESSOR CLUTCH - TYPICAL
1 - CLUTCH PLATE
2 - SHAFT KEY (not used on KJ)
3 - ROTOR
4 - COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
24 - 10 CONTROLSDR
A/C COMPRESSOR CLUTCH (Continued)

(11) Install the puller through-bolts (Special Tool
C-6461 or equivalent) through the puller flange and
into the jaws of the rotor puller and tighten (Fig. 5).
Turn the puller center bolt clockwise until the rotor
is free.
CAUTION: DO NOT APPLY FORCE TO THE END OF
THE COMPRESSOR SHAFT.
(12) Remove the screw and retainer from the
clutch coil lead wire harness on the compressor front
housing (Fig. 6).
(13) Remove the snap ring from the compressor
hub and remove the clutch field coil (Fig. 7). Slide
the clutch field coil off of the compressor hub.
Fig. 2 CLUTCH NUT REMOVE - Typical
1 - CLUTCH PLATE
2 - SPANNER
Fig. 3 EXTERNAL SNAP RING REMOVE - Typical
1 - PULLEY
2 - SNAP RING PLIERS
Fig. 4 SHAFT PROTECTOR AND PULLER - Typical
1 - PULLER JAW
2 - SHAFT PROTECTOR
Fig. 5 INSTALL PULLER PLATE - Typical
1 - PULLER JAW
2 - PULLER
Fig. 6 CLUTCH COIL LEAD WIRE HARNESS -
Typical
1 - COIL
2 - COIL WIRE
3 - RETAINER SCREW
DRCONTROLS 24 - 11
A/C COMPRESSOR CLUTCH (Continued)

NOTE: The air gap is determined by the spacer
shims. When installing an original, or a new clutch
assembly, try the original shims first. When install-
ing a new clutch onto a compressor that previously
did not have a clutch, use a 1.0, 0.50, and 0.13 mil-
limeter (0.040, 0.020, and 0.005 inch) shims from the
new clutch hardware package that is provided with
the new clutch.
(9) To complete the procedure, (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/A/C
COMPRESSOR - INSTALLATION).
A/C COMPRESSOR CLUTCH
RELAY
DESCRIPTION
The compressor clutch relay is a International
Standards Organization (ISO) micro-relay. The termi-
nal designations and functions are the same as a con-
ventional ISO relay. However, the micro-relay
terminal orientation (footprint) is different, the cur-
rent capacity is lower, and the relay case dimensions
are smaller than those of the conventional ISO relay.
The compressor clutch relay is located in the Power
Distribution Center (PDC) in the engine compart-
ment. Refer to the PDC label for relay identification
and location.
OPERATION
The compressor clutch relay is a electromechanical
device that switches battery current to the compres-
sor clutch coil when the Powertrain Control Module
(PCM) grounds the coil side of the relay. The PCM
responds to inputs from the A/C Heater mode control
switch, the A/C low pressure switch, and the A/C
high pressure switch. (Refer to 24 - HEATING & AIR
CONDITIONING/CONTROLS/A/C COMPRESSOR
CLUTCH RELAY - DIAGNOSIS AND TESTING)
The compressor clutch relay cannot be repaired
and, if faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH RELAY
RELAY TEST
The compressor clutch relay (Fig. 10) is located in
the Power Distribution Center (PDC). Refer to the
PDC label for relay identification and location.
Remove the relay from the PDC to perform the fol-
lowing tests:
(1) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 2. If not OK, replace the faulty relay.(2) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 67.5 to 82.5 ohms. If OK, go to
Step 3. If not OK, replace the faulty relay.
(3) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, see Relay Circuit Test. If not OK,
replace the faulty relay.
RELAY CIRCUIT TEST
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information).
(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
Fig. 10 COMPRESSOR CLUTCH RELAY
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
DRCONTROLS 24 - 13
A/C COMPRESSOR CLUTCH (Continued)