Engine system DODGE RAM 2003 Service Repair Manual

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

coil. To maintain minimum evaporator temperature
and prevent evaporator freezing, the A/C Fin Probe
which is located in the evaporator cycles the com-
pressor clutch by sending an A/C request to the
JTEC which in turn processes this piece of informa-
tion and if all conditions are met cycles the compres-
sor clutch.
OPERATION - REFRIGERANT SYSTEM SERVICE
PORT
The low pressure service port is located on the suc-
tion refrigerant line, near the accumulator. The high
pressure service port is located on the liquid line at
the passenger side of the engine compartment, near
the condenser.
Each of the service ports has a threaded plastic
protective cap installed over it from the factory. After
servicing the refrigerant system, always reinstall
both of the service port caps.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE
The air conditioning system is designed to provide
the passenger compartment with low temperature
and low humidity air. The evaporator, located in the
HVAC housing on the dash panel below the instru-
ment panel, is cooled to temperatures near the freez-
ing point. As warm damp air passes through the
cooled evaporator, the air transfers its heat to the
refrigerant in the evaporator and the moisture in the
air condenses on the evaporator fins. During periods
of high heat and humidity, an air conditioning sys-
tem will be more effective in the Recirculation Mode.
With the system in the Recirculation Mode, only air
from the passenger compartment passes through the
evaporator. As the passenger compartment air dehu-
midifies, the air conditioning system performance
levels improve.
Humidity has an important bearing on the temper-
ature of the air delivered to the interior of the vehi-
cle. It is important to understand the effect that
humidity has on the performance of the air condition-
ing system. When humidity is high, the evaporator
has to perform a double duty. It must lower the air
temperature, and it must lower the temperature of
the moisture in the air that condenses on the evapo-
rator fins. Condensing the moisture in the air trans-
fers heat energy into the evaporator fins and tubing.
This reduces the amount of heat the evaporator can
absorb from the air. High humidity greatly reduces
the ability of the evaporator to lower the temperature
of the air.
However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Remov-
ing some of the moisture out of the air entering the
vehicle adds to the comfort of the passengers.
Although, an owner may expect too much from the
air conditioning system on humid days. A perfor-
mance test is the best way to determine whether the
system is performing up to standard. This test also
provides valuable clues as to the possible cause of
trouble with the air conditioning system.
Before proceeding, (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNING) and
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - CAUTION). The air temperature in
the test room and in the vehicle must be a minimum
of 21É C (70É F) for this test.
(1) Connect a tachometer and a manifold gauge set
or A/C recycling/charging station.
(2) Set the A/C Heater mode control switch knob in
the Recirculation Mode position, the temperature
control knob in the full cool position, and the blower
motor switch knob in the highest speed position.
Fig. 1 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 - 2 HEATING & AIR CONDITIONINGDR
HEATING & AIR CONDITIONING (Continued)

(3) Start the engine and hold the idle at 1,000 rpm
with the compressor clutch engaged.
(4) The engine should be at operating temperature.
The doors and windows must be closed.
(5) Insert a thermometer in the driver side center
A/C (panel) outlet. Operate the engine for five min-
utes.
(6) The compressor clutch may cycle, depending
upon the ambient temperature and humidity.
(7) With the compressor clutch engaged, record the
discharge air temperature and the compressor dis-
charge pressure.(8) Compare the discharge air temperature to the
Performance Temperature and Pressure chart. If the
discharge air temperature is high, (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
DIAGNOSIS AND TESTING - REFRIGERANT SYS-
TEM LEAKS) and (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - SPECIFICATIONS -
CHARGE CAPACITY).
Performance Temperature and Pressure
Ambient Air
Temperature21É C
(70É F)27É C
(80É F)32É C
(90É F)38É C
(100É F)43É C
(110É F)
Air Temperature at
Center Panel Outlet7É C
(45É F)7É C
(45É F)13É C
(55É F)13É C
(55É F)18É C
(64É F)
Compressor Inlet
Pressure at Service
Port (low Side)138 to 207 kPa
(20 to 30 psi)172 to 241
kPa
(25 to 35 psi)207 to 276
kPa
(30 to 40 psi)241 to 310
kPa
(35 to 45 psi)276 to 345 kPa
(40 to 50 psi)
Condensor Out
Pressuree at Service
Port (High Side)1034 to 1724
kPa
(150 to 250
psi)1379 to 2068
kPa
(200 to 300
psi)1724 to 2413
kPa
(250 to 350
psi)1999 to 2689
kPa
(290 to 390
psi)2413 to 2965
kPa
(350 to 430 psi)
(9) Compare the compressor discharge pressure to
the Performance Temperature and Pressure chart. Ifthe compressor discharge pressure is high, see the
Pressure Diagnosis chart.
Pressure Diagnosis
Condition Possible Causes Correction
Constant compressor
engagement and warm air
from passenger vents.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.
Equal pressures, but the
compressor clutch does not
engage.1. No refrigerant in the
refrigerant system.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. Faulty fuse. 2. Check the fuses in the Power Distribution
Center and the junction block. Repair the shorted
circuit or component and replace the fuses, if
required.
3. Faulty a/c compressor
clutch coil.3. See A/C Compressor/Diagnosis and Testing -
Compressor Clutch Coil in this group. Test the
compressor clutch coil and replace, if required.
DRHEATING & AIR CONDITIONING 24 - 3
HEATING & AIR CONDITIONING (Continued)

Pressure Diagnosis
Condition Possible Causes Correction
4. Air in the refrigerant
system.4. 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.
5. Engine overheating. 5. Refer to Cooling for more information. Test the
cooling system and repair, if required.
The low side pressure is too
high, and the 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. Fixed orifice tube not
installed.2. See A/C Orifice Tube in this group. Replace
the liquid line, if required.
3. Faulty compressor. 3. See A/C Compressor in this group. Replace
the compressor, if required.
The low side pressure is too
low, and the high side
pressure is too high.1. Restricted refrigerant flow
through the refrigerant lines.1. See Liquid, Suction, and Discharge Line 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 fixed orifice tube.2. See A/C Orifice Tube in this group. Replace
the liquid line, if required.
3. Restricted refrigerant flow
through the condenser.3. See A/C Condenser in this group. Replace the
restricted condenser, if required.
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 at
normal 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)
DRHEATING & AIR CONDITIONING 24 - 5
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)

INSTALLATION
(1) Plug the two wire harness connectors into the
back of the A/C Heater control.
(2) Position the A/C Heater control in the instru-
ment panel bezel and secure it with four screws.
Tighten the screws to 2.2 N´m (20 in. lbs.).
(3) Reinstall the center bezel onto the instrument
panel(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL CENTER BEZEL - INSTALLA-
TION).
(4) Connect the battery negative cable.
A/C PRESSURE TRANSDUCER
DESCRIPTION - A/C PRESSURE TRANSDUCER
The A/C pressure transducer is a switch that is
installed on a fitting located on the refrigerant dis-
charge line between the compressor and the conden-
sor in the front corner of the engine compartment. An
internally threaded hex fitting on the transducer con-
nects it to the externally threaded Schrader-type fit-
ting on the liquid line. A rubber O-ring seals the
connection between the transducer and the discharge
line fitting. Three terminals within a molded plastic
connector receptacle on the top of the transducer con-
nect it to the vehicle electrical system through a take
out and connector of the headlamp and dash wire
harness.
The A/C pressure transducer cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
OPERATION
The A/C pressure transducer monitors the pres-
sures in the high side of the refrigerant system
through its connection to a fitting on the discharge
line. The transducer will change its internal resis-
tance in response to the pressures it monitors. The
Powertrain Control Module (PCM) provides a five
volt reference signal and a sensor ground to the
transducer, then monitors the output voltage of the
transducer on a sensor return circuit to determine
refrigerant pressure. The PCM is programmed to
respond to this and other sensor inputs by controlling
the operation of the air conditioning compressor
clutch and the radiator cooling fan to help optimize
air conditioning system performance and to protect
the system components from damage. The A/C pres-
sure transducer input to the PCM will also prevent
the air conditioning compressor clutch from engaging
when ambient temperatures are below about 10É C
due to the pressure/temperature relationship of the
refrigerant. The Schrader-type valve in the discharge
line fitting permits the A/C pressure transducer to be
removed or installed without disturbing the refriger-
ant in the system. The A/C pressure transducer is
diagnosed using a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
DIAGNOSIS AND TESTING - A/C PRESSURE
TRANSDUCER
The A/C pressure transducer is tested using a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information. Before testing the A/C pressure
transducer, be certain that the transducer wire har-
ness connection is clean of corrosion and properly
connected. For the air conditioning system to operate,
Fig. 12 Dual Zone A/C Control
1 - A/C Button
2 - Max. A/C Button
3 - Sideview Mirror Defrost Button (if equiped)
4 - Mounting Tabs (4)
5 - Driverside Temperature Control
6 - Passengerside Temperature Control
7 - Mode Control
8 - Blower Motor Speed Control
Fig. 13 HVAC Control - (Rear View- typical)
1 - Mounting Tabs (4)
2 - Mounting Screws (4)
3 - HVAC Control Connector
4 - Heated Sideview Mirror Connector
5 - HVAC Control Assembly
DRCONTROLS 24 - 15
A/C HEATER CONTROL (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)