ECU DODGE RAM 2003 Service Repair Manual

(3) Disconnect the HVAC wire harness connector
for the recirculation door actuator from the actuator
connector receptacle (Fig. 18).
(4) Remove the two screws that secure the recircu-
lation door actuator to the intake air housing.(5) Remove the recirculation door actuator from
the intake air housing.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Position the recirculation door actuator onto
the intake air housing. If necessary, rotate the actua-
tor slightly to align the splines on the actuator out-
put shaft with those in the recirculation air door.
(2) Install and tighten the two screws that secure
the recirculation door actuator to the lower intake air
housing. Tighten the screws to 2 N´m (17 in. lbs.).
(3) Reconnect the HVAC wire harness connector
for the recirculation door actuator to the actuator
connector receptacle.
(4) Install the Instrument Panel(Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - INSTALLATION).
(5) Reconnect the battery negative cable.
(6) Perform the heater-A/C control calibration pro-
cedure. (Refer to 24 - HEATING & AIR CONDITION-
ING/CONTROLS - FRONT/A/C-HEATER CONTROL
- STANDARD PROCEDURE - HEATER-A/C CON-
TROL CALIBRATION).
Fig. 18 HVAC Housing - Dual Zone Shown (Typical -
Single Zone)
1 - Mounting Nut
2 - Passenger Blend Door Actuator (dual zone)
3 - Mounting Nut
4 - Air Intake Spacer
5 - Recirculation Door Actuator
6 - Recirculation Door Assembly
7 - Driver Side Blend Door Actuator
8 - HVAC Housing
9 - Mounting Screw
10 - Defroster Door Actuator
11 - Panel Actuator
DRCONTROLS 24 - 23
RECIRCULATION DOOR ACTUATOR (Continued)

DIAGNOSIS AND TESTING - BLOWER MOTOR
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information). Possible causes of
an inoperative blower motor include:
²Faulty fuse
²Faulty blower motor circuit wiring or wire har-
ness connectors
²Faulty blower motor resistor
²Faulty blower motor relay
²Faulty blower motor switch
²Faulty A/C Heater mode control switch
²Faulty blower motor.
Possible causes of the blower motor not operating
in all speeds include:
²Faulty blower motor switch
²Faulty blower motor resistor
²Faulty blower motor circuit wiring or wire har-
ness connectors.
VIBRATION
Possible causes of blower motor vibration include:
²Improper blower motor mounting
²Improper blower wheel mounting
²Blower wheel out of balance or bent
²Blower motor faulty.
NOISE
To verify that the blower is the source of the noise,
unplug the blower motor wire harness connector and
operate the HVAC system. If the noise goes away,
possible causes include:
²Foreign material in the HVAC housing
²Improper blower motor mounting
²Improper blower wheel mounting
²Blower motor faulty.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERINGCOLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
The blower motor is located on the passenger side
of the vehicle under the dash
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the blower motor wire harness connec-
tor (Fig. 3).
(3) Remove the three screws that secure the
blower motor and wheel assembly to the HVAC hous-
ing.
(4) Rotate and tilt the blower motor unit as needed
for clearance to remove the blower motor and wheel
from the HVAC housing.
INSTALLATION
(1) Align and install the blower motor and wheel
assembly into the HVAC housing.
(2) Install the three mounting screws and tighten
to 2.2 N´m (20 in. lbs.).
Fig. 3 Blower Motor Assembly- (Case Removed
from vehicle for graphic)
1 - Blower Motor Resistor Mounting Screws (2)
2 - Blower Motor Resistor
3 - Blower Motor Resistor Connector
4 - Blower Motor Mounting Screw
5 - Blower Motor Assmebly
6 - Blower Motor Wire
7 - Blower Motor Mounting Screw
8 - HVAC Housing
9 - Blower Motor Wire Hold Down
10 - Blower Motor Mounting Screw
24 - 26 DISTRIBUTIONDR
BLOWER MOTOR (Continued)

(3) Plug in the blower motor wire harness connec-
tor.
(4) Connect the battery negative cable.
DEFROST DOOR
REMOVAL - DEFROST DOOR
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
WARNING: (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - WARNING) and (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING - CAU-
TION).
(1) Recover refrigerant(Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - STANDARD
PROCEDURE).
(2) Remove and disassemble the HVAC housing.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - DISASSEMBLY)
(3) Remove the defrost door actuator.
(4) Remove the defrost door from the HVAC hous-
ing, by first removing the actuator if not already
removed. Then carefully move the door so that one
pivot point cleans then tilt and lift the door out of
the HVAC housing.
INSTALLATION - DEFROST DOOR
(1) Install the defrost door in the HVAC housing.
(2) Install the defrost door actuator.
(3) Assemble the HVAC housing. (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - ASSEMBLY)
(4) Install the HVAC housing in the vehicle. (Refer
to 24 - HEATING & AIR CONDITIONING/DISTRI-
BUTION/HVAC HOUSING - INSTALLATION)
(5) Run calibration test.
FLOOR DISTRIBUTION DUCTS
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Remove the screws that secure the floor duct to
the HVAC housing.
(2) Remove the floor duct from the HVAC housing.
INSTALLATION
(1) Install the floor duct on the HVAC housing.
(2) Install the screws that secure the floor duct to
the HVAC housing. Tighten the mounting screws to
2.2 N´m (20 in. lbs.).
(3) Install the battery negative cable.
HVAC HOUSING
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel from the vehi-
cle(Refer to 23 - BODY/INSTRUMENT PANEL -
REMOVAL).
DRDISTRIBUTION 24 - 27
BLOWER MOTOR (Continued)

(3) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY)
(4) Disconnect the liquid line refrigerant line fit-
ting from the evaporator inlet tube (Fig. 4). (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING
- STANDARD PROCEDURE - A/C LINE COU-
PLERS)
(5) Disconnect the accumulator inlet tube refriger-
ant line fitting from the evaporator outlet tube.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE - A/C LINE
COUPLERS) Install plugs in, or tape over all of the
opened refrigerant line fittings.
(6) Drain the engine cooling system(Refer to 7 -
COOLING - STANDARD PROCEDURE).(7) Disconnect the heater hoses from the heater
core tubes. Install plugs in, or tape over the opened
heater core tubes.
(8) Unplug all electrical connectors from the actua-
tors and blower motor.
(9) Remove the nuts from the HVAC housing
mounting studs.
(10) Remove the HVAC housing from inside the
vehicle taking care not to allow any remaining cool-
ant to drain on the vehicles interior.
DISASSEMBLY
(1) Remove the HVAC housing from the vehicle
and place it on the workbench. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/HVAC
HOUSING - REMOVAL)
(2) Unplug the electrical connectors from each
actuator.
(3) Remove the HVAC assembly wiring harness
from the HVAC case.
(4) Remove the blower motor and blower wheel
unit from the HVAC housing. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/
BLOWER MOTOR - REMOVAL)
(5) Remove the heater core mounting screws and
carefully remove the heater core assembly(Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING/
HEATER CORE - REMOVAL).
(6) Carefully remove the foam seals from the
heater core and evaporator coil tube mounting flange
of the HVAC housing. If the either seal is deformed
or damaged it must be replaced.
(7) Use a screwdriver to pry off the four snap clips
that help secure the upper and lower HVAC housing
halves together.
(8) Remove the screws that secure the upper and
lower HVAC housing halves together.
(9) Carefully separate the upper HVAC housing
from the lower half.
ASSEMBLY
(1) Assemble the upper HVAC housing half to the
lower half. During assembly, be certain of the follow-
ing.
(a) That each of the mode door pivot shaft ends
and the temperature blend door shafts are properly
engaged in there pivot holes.
(b) That the blower motor is properly indexed
and installed.
(c) If the unit is equipped with air conditioning,
that the evaporator coil tube rubber seal is prop-
erly positioned in the grooves in both the upper
and lower HVAC housing halves.
(d) That the evaporator drain opening is clean.
(e) That the evaporator drain shield is installed
correctly.
Fig. 4 HVAC Housing - Dual Zone Shown (Typical -
Single Zone)
1 - Mounting Nut
2 - Passenger Blend Door Actuator (dual zone)
3 - Mounting Nut
4 - Air Intake Spacer
5 - Recirculation Door Actuator
6 - Recirculation Door Assembly
7 - Driver Side Blend Door Actuator
8 - HVAC Housing
9 - Mounting Screw
10 - Defroster Door Actuator
11 - Panel Actuator
24 - 28 DISTRIBUTIONDR
HVAC HOUSING (Continued)

(2) Install the screws and snap clips that secure
the upper and lower HVAC housing halves to each
other. Tighten the screws to 2.2 N´m (20 in. lbs.).
(3) Install the blower motor and wheel unit in the
HVAC housing. (Refer to 24 - HEATING & AIR CON-
DITIONING/DISTRIBUTION/BLOWER MOTOR -
INSTALLATION)
(4) Install the foam seals on the flanges around
the heater core and evaporator coil tube mounting
flange of the HVAC housing. Repair or replace any
seals as required.
(5) Install the electrical wiring harness for the
acutators. Make sure the wires are routed through
all wiring retainers, replace any retainers that are
damaged or missing.
(6) Connect the wiring harness to each actuator,
making sure each connector is securely attached.
INSTALLATION
WARNING: IF THE VEHICLE IS EQUIPPED WITH AIR
CONDITIONING, REVIEW THE WARNINGS AND
CAUTIONS IN PLUMBING BEFORE PERFORMING
THE FOLLOWING OPERATION. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - WARNING)
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - CAUTION) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION -
REFRIGERANT HOSES/LINES/TUBES PRECAU-
TIONS)
(1) Position the HVAC housing to the dash panel.
Be certain that the evaporator condensate drain tube
and the housing mounting studs are inserted into
their correct mounting holes.
(2) Install and tighten the nuts onto the HVAC
housing mounting studs. Tighten the nuts to 6.2 N´m
(55 in.lbs.).
(3) Connect the HVAC system electrical connec-
tors.
(4) Unplug or remove the tape from the heater
core tubes. Connect the heater hoses to the heater
core tubes and fill the engine cooling system(Refer to
7 - COOLING/ENGINE - STANDARD PROCE-
DURE).
(5) Unplug or remove the tape from the liquid line
and the evaporator inlet tube fittings. Connect the
liquid line coupler to the evaporator inlet tube. (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE - A/C LINE COU-
PLERS)(6) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
(8) Install the instrument panel in the vehicle(Re-
fer to 23 - BODY/INSTRUMENT PANEL - INSTAL-
LATION).
(9) Connect the battery negative cable.
(10) Start the engine and check for proper opera-
tion of the heating and air conditioning systems.
(11) Run the calibration procedure.
INSTRUMENT PANEL DUCTS
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the HVAC assembly from the vehi-
cle(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL).
(3) Disasemble the HVAC housing(Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - DISASSEMBLY).
(4) Remove the panel door actuator from the hous-
ing if not already removed.
(5) With the actuator removed you can take the
door and shift it so that one pivot point will clear the
housing. You can then tilt the door and remove it
from the housing.
INSTALLATION
(1) Take the door and tilt it so one pivot point is
installed. The carfully install the second pivot point.
Check to be sure no binding of the door is occuring,
repair as required.
(2) Reassemble the HVAC housing(Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - ASSEMBLY).
(3) Install the HVAC assembly into the vehicle(Re-
fer to 24 - HEATING & AIR CONDITIONING/DIS-
TRIBUTION/INSTRUMENT PANEL DUCTS -
INSTALLATION).
(4) Connect the battery negative cable.
DRDISTRIBUTION 24 - 29
HVAC HOUSING (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - REFRIGERANT
SYSTEM EVACUATE...................51
STANDARD PROCEDURE- REFRIGERANT
RECOVERY..........................52
STANDARD PROCEDURE- REFRIGERANT
SYSTEM CHARGE.....................52
REFRIGERANT LINE COUPLER
DESCRIPTION.........................52OPERATION...........................52
REMOVAL.............................52
INSTALLATION.........................53
REFRIGERANT OIL
DESCRIPTION.........................54
OPERATION...........................54
STANDARD PROCEDURE - REFRIGERANT
OIL LEVEL...........................54
PLUMBING
DESCRIPTION - REFRIGERANT LINE
The refrigerant lines and hoses are used to carry
the refrigerant between the various air conditioning
system components. A barrier hose design with a
nylon tube, which is sandwiched between rubber lay-
ers, is used for the R-134a air conditioning system on
this vehicle. This nylon tube helps to further contain
the R-134a refrigerant, which has a smaller molecu-
lar structure than R-12 refrigerant. The ends of the
refrigerant hoses are made from lightweight alumi-
num or steel, and commonly use braze-less fittings.
Any kinks or sharp bends in the refrigerant plumb-
ing will reduce the capacity of the entire air condi-
tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from an exhaust manifold.
OPERATION- REFRIGERANT LINES
High pressures are produced in the refrigerant sys-
tem when the air conditioning compressor is operat-
ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
The refrigerant lines and hoses are coupled with
other components of the HVAC system with either 3
O-ring spring lock couplings or dual axes seals.
The refrigerant lines and hoses cannot be repaired
and, if faulty or damaged, they must be replaced.
WARNING
SERVICE WARNINGS
WARNING: THE AIR CONDITIONING SYSTEM CON-
TAINS REFRIGERANT UNDER HIGH PRESSURE.
SEVERE PERSONAL INJURY MAY RESULT FROM
IMPROPER SERVICE PROCEDURES. REPAIRS
SHOULD ONLY BE PERFORMED BY QUALIFIED
SERVICE PERSONNEL.
AVOID BREATHING THE REFRIGERANT AND
REFRIGERANT OIL VAPOR OR MIST. EXPOSURE
MAY IRRITATE THE EYES, NOSE, AND/OR THROAT.
WEAR EYE PROTECTION WHEN SERVICING THE
AIR CONDITIONING REFRIGERANT SYSTEM. SERI-
OUS EYE INJURY CAN RESULT FROM DIRECT
CONTACT WITH THE REFRIGERANT. IF EYE CON-
TACT OCCURS, SEEK MEDICAL ATTENTION IMME-
DIATELY.
DO NOT EXPOSE THE REFRIGERANT TO OPEN
FLAME. POISONOUS GAS IS CREATED WHEN
REFRIGERANT IS BURNED. AN ELECTRONIC LEAK
DETECTOR IS RECOMMENDED.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE THE WORK AREA BEFORE RESUMING
SERVICE. LARGE AMOUNTS OF REFRIGERANT
RELEASED IN A CLOSED WORK AREA WILL DIS-
PLACE THE OXYGEN AND CAUSE SUFFOCATION.
THE EVAPORATION RATE OF R-134a REFRIGER-
ANT AT AVERAGE TEMPERATURE AND ALTITUDE
IS EXTREMELY HIGH. AS A RESULT, ANYTHING
THAT COMES IN CONTACT WITH THE REFRIGER-
ANT WILL FREEZE. ALWAYS PROTECT THE SKIN
OR DELICATE OBJECTS FROM DIRECT CONTACT
WITH THE REFRIGERANT.
THE R-134a SERVICE EQUIPMENT OR THE VEHI-
CLE REFRIGERANT SYSTEM SHOULD NOT BE
PRESSURE TESTED OR LEAK TESTED WITH COM-
PRESSED AIR. SOME MIXTURES OF AIR AND
R-134a HAVE BEEN SHOWN TO BE COMBUSTIBLE
AT ELEVATED PRESSURES. THESE MIXTURES ARE
POTENTIALLY DANGEROUS, AND MAY RESULT IN
FIRE OR EXPLOSION CAUSING INJURY OR PROP-
ERTY DAMAGE.
24 - 32 PLUMBINGDR

nents, caused by condenser air flow restriction or an
overcharge of refrigerant.
OPERATION
OPERATION
The compressor is driven by the engine through an
electric clutch, drive rotor and belt arrangement. The
compressor is lubricated by refrigerant oil that is cir-
culated throughout the refrigerant system with the
refrigerant.
The compressor draws in low-pressure refrigerant
vapor from the evaporator through its suction port. It
then compresses the refrigerant into a high-pressure,
high-temperature refrigerant vapor, which is then
pumped to the condenser through the compressor dis-
charge port.
The compressor cannot be repaired. If faulty or
damaged, the entire compressor assembly must be
replaced. The compressor clutch, pulley and clutch
coil are available for service.
OPERATION - HIGH PRESSURE RELIEF VALVE
The high pressure relief valve vents the system
when a discharge pressure of 3445 to 4135 kPa (500
to 600 psi) or above is reached. The valve closes
when a minimum discharge pressure of 2756 kPa
(400 psi) is reached.
The high pressure relief valve vents only enough
refrigerant to reduce the system pressure, and then
re-seats itself. The majority of the refrigerant is con-
served in the system. If the valve vents refrigerant, it
does not mean that the valve is faulty.
The high pressure relief valve is a factory-cali-
brated unit. The valve cannot be adjusted or
repaired, and must not be removed or otherwise dis-
turbed. The valve is only serviced as a part of the
compressor assembly.
DIAGNOSIS AND TESTING - A/C COMPRESSOR
NOISE
When investigating an air conditioning related
noise, you must first know the conditions under
which the noise occurs. These conditions include:
weather, vehicle speed, transmission in gear or neu-
tral, engine speed, engine temperature, and any
other special conditions. Noises that develop during
air conditioning operation can often be misleading.
For example: What sounds like a failed front bearing
or connecting rod, may be caused by loose bolts, nuts,
mounting brackets, or a loose compressor clutch
assembly.
Drive belts are speed sensitive. At different engine
speeds and depending upon belt tension, belts can
develop noises that are mistaken for a compressornoise. Improper belt tension can cause a misleading
noise when the compressor clutch is engaged, which
may not occur when the compressor clutch is disen-
gaged. Check the serpentine drive belt condition and
tension as described in Cooling before beginning this
procedure.
(1) Select a quiet area for testing. Duplicate the
complaint conditions as much as possible. Switch the
compressor on and off several times to clearly iden-
tify the compressor noise. Listen to the compressor
while the clutch is engaged and disengaged. Probe
the compressor with an engine stethoscope or a long
screwdriver with the handle held to your ear to bet-
ter localize the source of the noise.
(2) Loosen all of the compressor mounting hard-
ware and retighten. Tighten the compressor clutch
mounting nut. Be certain that the clutch coil is
mounted securely to the compressor, and that the
clutch plate and rotor are properly aligned and have
the correct air gap. (Refer to 24 - HEATING & AIR
CONDITIONING/CONTROLS/A/C COMPRESSOR
CLUTCH - INSTALLATION)
(3) To duplicate a high-ambient temperature condi-
tion (high head pressure), restrict the air flow
through the condenser. Install a manifold gauge set
to be certain that the discharge pressure does not
exceed 2760 kPa (400 psi).
(4) Check the refrigerant system plumbing for
incorrect routing, rubbing or interference, which can
cause unusual noises. Also check the refrigerant lines
for kinks or sharp bends that will restrict refrigerant
flow, which can cause noises. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAU-
TION)
(5) If the noise is from opening and closing of the
high pressure relief valve, evacuate and recharge the
refrigerant system. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM EVACUATE)
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE - REFRIG-
ERANT SYSTEM CHARGE) If the high pressure
relief valve still does not seat properly, replace the
compressor.
(6) If the noise is from liquid slugging on the suc-
tion line. Check the refrigerant oil level and the
refrigerant system charge. (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/REFRIGER-
ANT OIL - STANDARD PROCEDURE) (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
SPECIFICATIONS - CHARGE CAPACITY) If either
is out of specification range reclaim, evacuate and
recharge the refrigerent system(Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/REFRIG-
ERANT - STANDARD PROCEDURE), (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/RE-
24 - 36 PLUMBINGDR
A/C COMPRESSOR (Continued)

FRIGERANT - STANDARD PROCEDURE) and
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/REFRIGERANT - STANDARD PROCE-
DURE). If the liquid slugging condition continues
replace the accumulator(Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING/ACCUMULATOR
- REMOVAL). If after replaceing the accumulator the
slugging condition still exists then replace the com-
pressor.(Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING/A/C COMPRESSOR - REMOVAL)
(7) If the noise continues, replace the compressor
and repeat Step 1.
REMOVAL
REMOVAL
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
The compressor may be removed and repositioned
without disconnecting the refrigerant lines or dis-
charging the refrigerant system. Discharging is not
necessary if servicing the compressor clutch or clutch
coil, the engine, the cylinder head, or the generator.
(1) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY)
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the serpentine drive belt(Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Unplug the compressor clutch coil wire harness
connector.
(5) Remove the suction and discharge refrigerant
line manifold from the compressor. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/
SUCTION LINE - REMOVAL) (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C
DISCHARGE LINE - REMOVAL) Install plugs in, or
tape over all of the opened refrigerant fittings.
(6) Remove the bolts that secure the compressor to
the mounting bracket (Fig. 2).
(7) Remove the compressor from the mounting
bracket.
REMOVAL - 5.9L DIESEL ENGINE
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFOREPERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
The compressor may be removed and repositioned
without disconnecting the refrigerant lines or dis-
charging the refrigerant system. Discharging is not
necessary if servicing the compressor clutch or clutch
coil, the engine, the cylinder head, or the generator.
(1) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY)
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the serpentine drive belt(Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Unplug the compressor clutch coil wire harness
connector.
(5) Remove the bolt that secures the refrigerant
line manifold to the compressor. Install plugs in, or
tape over all of the opened refrigerant line fittings.
(6) Remove the four bolts that secure the compres-
sor to the mounting bracket (Fig. 3).
(7) Remove the a/c compressor from the mounting
bracket.
Fig. 2 A/C COMPRESSOR - 3.7L ENGINE- (typical
4.7, 5.7 & 8.0L)
1 - COMPRESSOR BOLT #1
2 - COMPRESSOR BOLT #2
3 - COMPRESSOR BOLT #3
4 - A/C COMPRESSOR
5 - A/C COMPRESSOR CLUTCH AND PULLEY
6 - COMPRESSOR MOUNT
DRPLUMBING 24 - 37
A/C COMPRESSOR (Continued)

(5) Disconnect the condenser cooling fan electric
connector.
(6) Remove the two nuts that secure the condenser
studs to the upper cross brace. (Fig. 5).
(7) Remove the condenser and fan assembly from
the vehicle.
REMOVAL - 5.9L DIESEL ENGINE
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
(1) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY)
(3) Remove the nut that secures the block fitting
to the stud on the condenser inlet, and disconnect the
discharge line from the condenser. Install plugs in, or
tape over all of the opened refrigerant line fittings.
(4) Disconnect the refrigerant line fitting that
secures the liquid line to the condenser outlet. (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE - A/C LINE COU-PLER) Install plugs in, or tape over all of the opened
refrigerant line fittings.
(5) On diesel engine models:
(a) Remove the two screws that secure the
brackets on the passenger side end of the con-
denser to the charge air cooler (Fig. 6).
(b) Remove the two nuts that secure the driver
side end of the condenser to the studs on the
charge air cooler.
(c) Remove the condenser from the vehicle.
REMOVAL - 8.0L Engine
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN TEH FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION(Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
WARNING) AND (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - CAUTION).
(1) Remove battery negative cable.
(2) Recover refrigerant from a/c system(Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
Fig. 5 Condenser Module
1 - Condensor Module Mounting Screw
2 - Front Cross Member
3 - Lower Module Mounting Flang
4 - Fan Assembly Mounting Screw
5 - Fan Assembly Mounting Screw
6 - Condensor Mounting Tabs
7 - Condensor Fan Assembly
8 - Fan Power Connector
9 - Condensor Module Mounting Screw
Fig. 6 CONDENSER - DIESEL ENGINE
1 - Discharge line to condenser
2 - Condensor mounting bolt
3 - Liquid Line
4 - Condenser mounting bolt
5 - A/C condenser
6 - Condenser mounting bolt
7 - Condenser mounting bolt
24 - 40 PLUMBINGDR
A/C CONDENSER (Continued)

AIR CONDITIONING/PLUMBING - STANDARD
PROCEDURE - A/C LINE COUPLERS)
(4) Remove the tape or plugs from the refrigerant
line fittings on the condenser inlet and the discharge
line. Connect the discharge line to the condenser
inlet. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - STANDARD PROCEDURE - A/C
LINE COUPLERS)
(5) Connect the battery negative cable.
(6) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
NOTE: If the condenser is replaced, add 30 millili-
ters (1 fluid ounce) of refrigerant oil to the refriger-
ant system. Use only refrigerant oil of the type
recommended for the compressor in the vehicle.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/REFRIGERANT OIL - DESCRIPTION)
INSTALLATION - 5.9L DIESEL ENGINE
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)(Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTION - REFRIGERANT HOSES/LINES/TUBES
PRECAUTIONS)
(1) On diesel engine models:
(a) Install the driver side condenser mounting
brackets over the two studs on the charge air
cooler.
(b) Install the two screws that secure the brack-
ets on the passenger side end of the condenser to
the charge air cooler. Tighten the mounting screws
to 10.5 N´m (95 in. lbs.).
(c) Install the two nuts that secure the driver
side end of the condenser to the studs on the
charge air cooler. Tighten the mounting nuts to
10.5 N´m (95 in. lbs.).
(2) Remove the plugs or tape from the refrigerant
line fittings on the liquid line and the condenser out-
let. Connect the liquid line to the condenser outlet.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE - A/C LINE
COUPLERS)(3) Install a new gasket and the discharge line
block fitting over the stud on the condenser inlet.
Tighten the mounting nut to 20 N´m (180 in. lbs.).
(4) Check that all of the condenser and radiator
air seals are in their proper locations.
(5) Connect the battery negative cable.
(6) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
NOTE: If the condenser is replaced, add 30 millili-
ters (1 fluid ounce) of refrigerant oil to the refriger-
ant system. Use only refrigerant oil of the type
recommended for the compressor in the vehicle.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/REFRIGERANT OIL - DESCRIPTION)
INSTALLATION - 8.0L Engine
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION(Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
WARNING) AND (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - CAUTION).
(1) If the condenser was removed from the shroud,
install it and tighten the mounting screws.
(2) Install the condenser and shroud in the vehicle.
Make sure the lower mounting flanges are positioned
correctly before installing the two mounting screws
to the radiator brace. Tighten the screws to spec.
(3) Remove and plugs or tape installed over the
condenser connections and the a/c lines.
(4) Install the lines to the condenser(Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/A/C
DISCHARGE LINE - INSTALLATION) and (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING/
SUCTION LINE - INSTALLATION).
(5) Install the hood latch assembly(Refer to 23 -
BODY/HOOD/LATCH - INSTALLATION).
(6) Install the front bumper assembly(Refer to 13 -
FRAME & BUMPERS/BUMPERS/FRONT BUMPER
- INSTALLATION).
(7) Evacuate the a/c system(Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE).
24 - 42 PLUMBINGDR
A/C CONDENSER (Continued)