Air conditioning DODGE RAM 1500 1998 2.G Repair Manual

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) or the Engine
Control Module (ECM) depending on engine applica-
tion, provides a five volt reference signal and a sen-
sor ground to the transducer, then monitors the
output voltage of the transducer on a sensor return
circuit to determine refrigerant pressure. The PCM/
ECM is programmed to respond to this and other
sensor inputs by controlling the operation of the air
conditioning compressor clutch and the radiator cool-
ing fan to help optimize air conditioning system per-
formance and to protect the system components from
damage. The A/C pressure transducer input to the
PCM/ECM will also prevent the air conditioning com-
pressor clutch from engaging when ambient temper-
atures are below about 10É C (50É F) 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 refrigerant 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,
an A/C pressure transducer voltage reading between
0.451 and 4.519 volts is required. Voltages outside
this range indicate a low or high refrigerant system
pressure condition to the Powertrain Control Module
(PCM) or Engine Control Module (ECM) depending
on engine application. The PCM/ECM is programmed
to respond to a low or high refrigerant system pres-
sure by suppressing operation of the compressor.
Refer to the A/C Pressure Transducer Voltage chart
for the possible conditions indicated by the trans-
ducer voltage reading.
A/C PRESSURE TRANSDUCER VOLTAGE
CHART
Voltage Possible Indication
0.0 1. No sensor supply voltage from
PCM/ECM.
2. Shorted sensor circuit.
3. Faulty transducer.
0.150 TO 0.450 1. Ambient temperature below
10É C (50É F).
2. Low refrigerant system
pressure.
0.451 TO 4.519 1. Normal refrigerant system
pressure.
4.520 TO 4.850 1. High refrigerant system
pressure.
5.0 1. Open sensor circuit.
2. Faulty transducer.
REMOVAL
NOTE: Note: It is not necessary to discharge the
refrigerant system to replace the A/C pressure
transducer.
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the wire harness connector from the
A/C pressure transducer.
(3) Remove the A/C pressure transducer from the
fitting on the discharge line (Fig. 15).
(4) Remove the O-ring seal from the A/C pressure
transducer fitting and discard.
INSTALLATION
NOTE: Replace the O-ring seal before installing the
A/C pressure transducer.
(1) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the A/C pressure
transducer fitting. Use only the specified O-rings as
they are made of a special material for the R-134a
system. Use only refrigerant oil of the type recom-
mended for the A/C compressor in the vehicle.
(2) Install and tighten the A/C pressure transducer
onto the discharge line fitting. The transducer should
be hand-tightened securely onto the discharge line
fitting.
(3) Connect the wire harness connector to the A/C
pressure transducer.
24 - 16 CONTROLSDR
A/C PRESSURE TRANSDUCER (Continued)

NOTE: The single zone heating and air conditioning
system is equipped with a single blend door actua-
tor. The dual zone system has two blend door
actuators, one for the driver side blend air door and
one for the passenger side blend air door. The
same service procedures can be used for each of
these actuators.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel from the vehicle
(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL ASSEMBLY - REMOVAL).
(3) Disconnect the wire harness connector from the
blend door actuator(s) (Fig. 16).
(4) Remove the screws that secure the blend door
actuator(s) to the HVAC housing.
(5) Remove the blend door actuator(s) from the
HVAC housing.INSTALLATION
(1) Position the blend door actuator(s) into the
HVAC housing. If necessary, rotate the actuator(s)
slightly to align the splines on the actuator output
sleeve(s) with those on the blend door linkage.
(2) Install and tighten the screws that secure the
blend door actuator(s) to the HVAC housing. Tighten
the screws to 2 N´m (17 in. lbs.).
(3) Connect the HVAC wire harness connector to
the blend door actuator(s).
(4) Install the instrument panel (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - INSTALLATION).
(5) Reconnect the battery negative cable.
BLOWER MOTOR RESISTOR
BLOCK
DESCRIPTION
The blower motor resistor is mounted to the bot-
tom side of the HVAC housing near the blower motor.
It can be accessed for service from underneath the
instrument panel.
OPERATION
The resistor has multiple resistor wires, each of
which will reduce the current flow to the blower
motor to change the blower motor speed by changing
the resistance in the blower motor ground path. The
blower motor switch directs the ground path through
the correct resistor wire to obtain the selected speed.
With the blower motor switch in the lowest speed
position, the ground path for the motor is applied
through all of the resistor wires. Each higher speed
selected with the blower motor switch applies the
blower motor ground path through fewer of the resis-
tor wires, increasing the blower motor speed. When
the blower motor switch is in the highest speed posi-
tion, the blower motor resistor is bypassed and the
blower motor receives a direct path to ground.
The blower motor resistor cannot be repaired and,
if faulty or damaged, it must be replaced.
Fig. 16 HVAC Housing - Dual Zone Shown, Single
Zone Typical
1 - NUT
2 - PASSENGER BLEND DOOR ACTUATOR
3 - NUT
4 - INLET BAFFLE
5 - RECIRCULATION DOOR ACTUATOR
6 - RECIRCULATION DOOR
7 - DRIVER SIDE BLEND DOOR ACTUATOR
8 - HVAC HOUSING
9 - BOLT
10 - DEFROSTER DOOR ACTUATOR
11 - MODE DOOR ACTUATOR
24 - 18 CONTROLSDR
BLEND DOOR ACTUATOR (Continued)

EVAPORATOR TEMPERATURE
SENSOR
DESCRIPTION
The evaporator temperature sensor is a two-wire
temperature sensing element located at the coldest
point on the face of the evaporator. The sensor is
attached to the evaporator coil fins. The evaporator
temperature sensor prevents condensation on the
evaporator coil from freezing and obstructing A/C
system air flow. The evaporator temperature sensor
cannot be adjusted or repaired and, if faulty or dam-
aged, it must be replaced.
OPERATION
The evaporator temperature sensor monitors the
temperature of the evaporator. The sensor will
change its internal resistance in response to the tem-
peratures it monitors. The A/C-heater control module
is connected to the sensor through a sensor ground
circuit and a sensor signal circuit. As the evaporator
temperature increases, the resistance of the sensor
decreases and the voltage monitored by the module
decreases. The module uses this monitored voltage
reading to an indication of the evaporator tempera-
ture. The A/C-heater control module is programmed
to respond to this input by cycling the air condition-
ing compressor clutch as necessary to optimize air
conditioning system performance and to protect the
system from evaporator freezing. The external loca-
tion of the sensor allows the sensor to be removed or
installed without disturbing the refrigerant in the
system. The evaporator temperature sensor is diag-
nosed using a DRBIIItscan tool. Refer to Body Diag-
nostic Procedures.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the HVAC housing from the vehicle
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL).
(3) Disconnect the HVAC wire harness connector
from the evaporator temperature sensor (Fig. 20).
(4) Disassemble the HVAC housing to gain access
to the evaporator coil (Refer to 24 - HEATING & AIR
CONDITIONING/DISTRIBUTION/HVAC HOUSING
- DISASSEMBLY).
(5) Remove the evaporator temperature sensor
probe from the evaporator coil (Fig. 21).
INSTALLATION
(1) Install the evaporator temperature sensor
probe into the evaporator coil.
Fig. 20 Evaporator Temperature Sensor Wire
Connector
1 - HVAC HOUSING
2 - EVAPORATOR TEMPERATURE SENSOR
3 - HVAC WIRE HARNESS
Fig. 21 Evaporator Temperature Sensor Probe
1 - EVAPORATOR COIL
2 - EVAPORATOR TEMPERATURE SENSOR PROBE
3 - BLEND DOOR
4 - HVAC HOUSING
24 - 22 CONTROLSDR

(2) Assemble the HVAC housing (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - ASSEMBLY).
(3) Connect the HVAC wire harness connector to
the evaporator temperature sensor.
(4) Install the HVAC housing (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/HVAC
HOUSING - INSTALLATION).
(5) Reconnect the battery negative cable.
MODE DOOR ACTUATOR
DESCRIPTION
The mode door actuator is a reversible 12-volt
Direct Current (DC) servo motor. The mode door
actuator is located on the HVAC housing, behind the
instrument panel and is mechanically connected to
the mode door.
The mode door actuator is interchangeable with
the actuators for the blend door(s), defrost door and
the recirculation door. Each actuator is contained
within an identical black molded plastic housing with
an integral wire connector receptacle. Integral
mounting tabs allow the actuator to be secured with
three screws to the HVAC housing. Each actuator
also has an identical output shaft with splines that
connects it to the linkage that drives the proper door.
The mode door actuator does not require mechanical
indexing to the mode door linkage, as it is electroni-
cally calibrated by the heater-A/C control module.
The mode door actuator cannot be adjusted or
repaired and, if damaged or faulty, it must be
replaced.
OPERATION
The mode door actuator is connected to the A/C-
heater control through the vehicle electrical system
by a dedicated two-wire lead and connector from the
HVAC wire harness. The mode door actuator can
move the mode door in two directions. When the A/C-
heater control pulls the voltage on one side of the
motor connection high and the other connection low,
the mode door will move in one direction. When the
A/C-heater control reverses the polarity of the volt-
age to the motor, the mode door moves in the oppo-
site direction. When the A/C-heater control makes
the voltage to both connections high or both connec-
tions low, the mode door stops and will not move.
These same motor connections also provide a feed-
back signal to the A/C-heater control. This feedback
signal allows the A/C-heater control to monitor the
operation and relative position of the mode door
actuator and the mode door. The A/C-heater control
learns the mode door stop positions during the cali-
bration procedure and will store a diagnostic troublecode (DTC) for any problems it detects in the mode
door actuator circuits.
The mode door actuator can be diagnosed using a
DRBIIItscan tool. Refer to Body Diagnostic Proce-
dures for more information. The mode door actuator
cannot be adjusted or repaired and, if damaged or
faulty, it must be replaced.
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 ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel from the vehicle
(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL ASSEMBLY - REMOVAL).
(3) Disconnect the wire harness connector from the
mode door actuator (Fig. 22).
(4) Remove the screws that secure the mode door
actuator to the HVAC housing.
(5) Remove the mode door actuator from the HVAC
housing.
INSTALLATION
(1) Position the mode door actuator onto the HVAC
housing. If necessary, rotate the actuator slightly to
align the splines on the actuator output sleeve with
those on the mode door linkage.
(2) Install and tighten the screws that secure the
mode door actuator to the HVAC housing. Tighten
the screws to 2 N´m (17 in. lbs.).
(3) Connect the HVAC wire harness connector to
the mode door actuator.
(4) Install the instrument panel (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - INSTALLATION).
(5) Reconnect the battery negative cable.
DRCONTROLS 24 - 23
EVAPORATOR TEMPERATURE SENSOR (Continued)

NOTE: The instrument panel air outlets are retained
into the outlet housings by a light snap fit.
(1) Using a trim stick or another suitable wide
flat-bladed tool, gently pry the panel air outlet(s) out
of the panel outlet housing(s) as required (Fig. 1).
INSTALLATION
(1) Position the air outlet(s) onto the outlet hous-
ing(s).
(2) Gently push the air outlet into the housing
until it snaps into position.
BLEND DOOR
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.NOTE: Vehicles equiped with single zone HVAC
systems have one blend door, dual zone systems
have two blend doors.
(1) Remove the HVAC housing from the vehicle
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL).
(2) Disassemble the HVAC housing (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - DISASSEMBLY).
(3) Remove the levers from the driver and/or pas-
senger side blend door (if equipped) (Fig. 2).
(4) Gently slide the drivers and/or passenger side
blend door toward the out side of the housing. Tilt
and lift the door(s) out of the housing.
(5) Inspect the blend door(s), seals and the HVAC
housing for damage or binding and repair or replace
components as required.
INSTALLATION
(1) Position the blend door pivot shafts into the
pivot hole and actuator in the bottom of the lower
half of the HVAC housing.
(2) Install the blend door(s) by carefully tipping
the doors into the HVAC housing, then sliding each
door into it's operating position.
(3) Install the levers to the driver and/or passen-
ger side blend door (if equipped).
(4) Assemble the HVAC housing (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - ASSEMBLY)
Fig. 1 Instrument Panel Air Outlets
1 - HEADLIGHT SWITCH
2 - AIR OUTLETS
3 - INSTRUMENT CLUSTER
4 - CLIMATE CONTROL
5 - RADIO
6 - AIRBAG
7 - GLOVE BOX
8 - HEATED SEAT SWITCH (IF EQUIPPED)
9 - TRANSFER CASE SWITCH (IF EQUIPPED)
10 - CIGAR LIGHTER
11 - CUP HOLDERS
12 - ASH TRAY (IF EQUIPPED)
13 - POWER OUTLET
Fig. 2 Blend Door - Dual Zone Shown, Single Zone
Typical
1 - PASSENGER SIDE BLEND DOOR LEVER
2 - PASSENGER SIDE BLEND DOOR
3 - EVAPORATOR TEMPERATURE SENSOR WIRE
4 - HVAC HOUSING
5 - A/C EVAPORATOR
6 - EVAPORATOR TEMPERATURE SENSOR PROBE
7 - DRIVER SIDE BLEND DOOR
8 - DRIVER SIDE BLEND DOOR LEVER
DRDISTRIBUTION 24 - 27
AIR OUTLETS (Continued)

(5) Install the HVAC housing (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/HVAC
HOUSING - INSTALLATION)
BLOWER MOTOR
DESCRIPTION
The blower motor and blower wheel are located in
the passenger side end of the HVAC housing, below
the glove box. The blower motor controls the velocity
of air flowing through the HVAC housing by spinning
a squirrel cage-type blower wheel within the housing
at the selected speed. The blower motor and wheel
can be removed from the housing inside the vehicle
without removing the instrument panel or HVAC
housing.
OPERATION
The blower motor will only operate with the igni-
tion switch in the On position and the A/C-heater
mode control switch in any position, except Off. The
blower motor receives a fused battery feed circuit
through a fuse in the Power Distribution Center
(PDC) whenever the ignition switch is in the On posi-
tion. Blower motor speed is controlled by regulating
the ground path through or around the blower motor
resistor block and through the A/C-heater blower
motor switch.
The blower motor and blower motor wheel are ser-
viced only as a unit and cannot be repaired and, if
faulty or damaged, must be replaced.
DIAGNOSIS AND TESTING - BLOWER MOTOR
BLOWER MOTOR INOPERATIVE
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.
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring, diagrams, proper wire and con-
nector repair procedures, further details on wire
harness routing and retention, as well as pin-out and
location views for the various wire harness connec-
tors, splices and grounds.
BLOWER MOTOR ELECTRICAL DIAGNOSIS
Refer to the Blower Motor Electrical Diagnosis
chart for basic checks of the blower motor circuit
(Fig. 3).
BLOWER MOTOR NOISE OR VIBRATION
Refer to the Blower Motor Noise/Vibration Diagno-
sis chart for basic checks of the blower motor when a
vibration or noise is present (Fig. 4).
24 - 28 DISTRIBUTIONDR
BLEND DOOR (Continued)

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.
NOTE: The blower motor is located on the passen-
ger side of the vehicle under the instrument panel.
The blower motor can be removed from the vehicle
without having to remove the HVAC housing.
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the wire harness connector from the
blower motor. (Fig. 5).
(3) Remove the three screws that secure the
blower motor to the HVAC housing.
(4) Remove the blower motor from the HVAC hous-
ing by rotating and tilting the blower motor as
needed for clearance.
INSTALLATION
(1) Align and install the blower motor into the
HVAC housing.
(2) Install the three screws that secure the blower
motor to the HVAC housing. Tighten the screws to
2.2 N´m (20 in. lbs.).
(3) Connect the wire harness connector to the
blower motor.
(4) Reconnect the battery negative cable.
DEFROST DOOR
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. THISIS 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 HVAC housing from the vehicle
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL).
(2) Disassemble the HVAC housing (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - DISASSEMBLY).
(3) Remove the defrost door actuator and sleeve
from the lower half of the HVAC housing (Fig. 6).
(4) Gently slide the defrost door toward the out-
side of the housing. Tilt and lift the door out of the
housing.
(5) Inspect the defrost door, seals and the HVAC
housing for damage or binding and repair or replace
components as required.
INSTALLATION
(1) Position the defrost door pivot shaft into the
pivot hole in the lower half of the HVAC housing.
(2) Install the defrost door actuator and sleeve.
(3) Assemble the HVAC housing (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - ASSEMBLY)
(4) Install the HVAC housing (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/HVAC
HOUSING - INSTALLATION)
Fig. 5 HVAC Blower Motor - Typical
1 - RESISTOR BLOCK SCREWS (2)
2 - BLOWER MOTOR RESISTOR BLOCK
3 - RESISTOR BLOCK WIRE CONNECTOR
4 - BLOWER MOTOR SCREW
5 - BLOWER MOTOR
6 - BLOWER MOTOR WIRE CONNECTOR
7 - BLOWER MOTOR SCREW
8 - HVAC HOUSING
9 - WIRE HARNESS RETAINER (2)
10 - BLOWER MOTOR SCREW
DRDISTRIBUTION 24 - 31
BLOWER MOTOR (Continued)

FLOOR DISTRIBUTION DUCT
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 HVAC housing from the vehicle
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL).
(2) Remove the screws that secure the floor distri-
bution duct to the bottom of the HVAC housing.
(3) Remove the floor distribution duct from the
HVAC housing.
Fig. 7 Defroster Duct
1 - SPEAKER WIRE HARNESS CONNECTOR
2 - DEFROSTER DUCT SCREWS (6)
3 - DEFROSTER DUCT ADAPTER4 - DEFROSTER DUCT ADAPTER SCREW
5 - DEFROSTER DUCT
Fig. 8 Floor Distribution Duct
1 - FLOOR DISTRIBUTION DUCT
2 - HVAC HOUSING
3 - SCREWS (5)
DRDISTRIBUTION 24 - 33
DEFROSTER DUCT (Continued)

INSTALLATION
(1) Install the floor distribution duct onto the bot-
tom of the HVAC housing.
(2) Install the five screws that secure the floor dis-
tribution duct to the HVAC housing. Tighten the
screws to 2.2 N´m (20 in. lbs.).
(3) Install the HVAC housing (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/HVAC
HOUSING - INSTALLATION).
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.
NOTE: The HVAC housing must be removed from
the vehicle and the two halves of the housing sep-
arated for service access of the heater core, evap-
orator coil, defrost door, blend door(s) and the
recirculation door.
(1) Disconnect and isolate the battery negative
cable.
(2) Drain the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(3) Recover the refrigerant from the refrigerant
system (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY).
(4) Disconnect the liquid refrigerant line fitting
from the evaporator inlet tube (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/REFRIG-
ERANT LINE COUPLER - REMOVAL). Discard the
O-ring seal and install plugs in, or tape over the
opened liquid refrigerant line fitting and evaporator
inlet tube.
(5) Remove the accumulator (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/ACCU-
MULATOR - REMOVAL). Discard the O-ring seals
and install plugs in, or tape over the opened refrig-
erant line fittings and evaporator outlet tube.(6) Disconnect the heater hoses from the heater
core tubes. Install plugs in, or tape over the opened
heater core tubes.
(7) Remove the powertrain control module (PCM)
from the engine compartment to gain access to the
HVAC housing retaining nuts (Refer to 8 - ELECTRI-
CAL/ELECTRONIC CONTROL MODULES/POWER-
TRAIN CONTROL MODULE - REMOVAL).
(8) Remove the two nuts from the HVAC housing
mounting studs in the engine compartment.
(9) Remove the instrument panel from the vehicle
(Refer to 23 - BODY/INSTRUMENT PANEL -
REMOVAL).
(10) Remove the bolt that secures the HVAC hous-
ing to the floor bracket located in the center of the
vehicle (Fig. 9).
(11) Remove the two nuts from the HVAC housing
mounting studs in the passenger compartment.
(12) Remove the HVAC housing from inside the
vehicle. Take care not to allow any remaining coolant
to drain onto the vehicles interior.
Fig. 9 HVAC Housing - Dual Zone Shown, Single
Zone Typical
1 - NUT
2 - PASSENGER BLEND DOOR ACTUATOR
3 - NUT
4 - INLET BAFFLE
5 - RECIRCULATION DOOR ACTUATOR
6 - RECIRCULATION DOOR
7 - DRIVER SIDE BLEND DOOR ACTUATOR
8 - HVAC HOUSING
9 - BOLT
10 - DEFROSTER DOOR ACTUATOR
11 - MODE DOOR ACTUATOR
24 - 34 DISTRIBUTIONDR
FLOOR DISTRIBUTION DUCT (Continued)

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) Disconnect the electrical connectors from the
blower motor, blower motor resistor block, evaporator
temperature sensor and each actuator (Fig. 10).
(3) Remove the HVAC wiring harness from the
HVAC housing.
(4) If necessary, remove the blower motor from
the HVAC housing (Refer to 24 - HEATING & AIR
CONDITIONING/DISTRIBUTION/BLOWER
MOTOR - REMOVAL).
(5) If necessary, remove the blower motor resistor
block from the HVAC housing (Refer to 24 - HEAT-
ING & AIR CONDITIONING/CONTROLS/BLOWER
MOTOR RESISTOR BLOCK - 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) Remove the screws that secure the heater core
in the HVAC housing and carefully remove the
heater core from the housing (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/HEATER
CORE - REMOVAL).(8) Use a screwdriver to pry off the four snap clips
that help secure the upper and lower HVAC housing
halves together.
(9) Remove the screws that secure the upper and
lower HVAC housing halves to each other and those
that secure the recirculation housing to the upper
HVAC housing.
(10) Carefully separate the recirculation housing
and the upper HVAC housing from the lower hous-
ing.
ASSEMBLY
(1) Position the upper HVAC housing to the lower
housing. During assembly, be certain of the following:
(a) That each of the door pivot shaft ends are
properly engaged in there pivot holes.
(b) That the evaporator drain opening is clean
and the drain foam seal is properly installed.
(2) Install the screws and snap clips that secure
the upper and lower HVAC housing halves to each
other and those that secure the recirculation housing
to the upper HVAC housing. Tighten the screws to
2.2 N´m (20 in. lbs.).
(3) Install the foam seals on the heater core and
evaporator coil tubes.
(4) If removed, install the blower motor resistor
block (Refer to 24 - HEATING & AIR CONDITION-
Fig. 10 HVAC Housing - Disassembled
1 - RECIRCULATION HOUSING
2 - RECIRC DOOR ACTUATOR
3 - DRIVER SIDE BLEND DOOR ACTUATOR
4 - FLOOR DISTRIBUTION DUCT
5 - DEFROST DOOR ACTUATOR
6 - PANEL DOOR ACTUATOR
7 - UPPER HVAC HOUSING
8 - PASSENGER SIDE BLEND DOOR ACTUATOR9 - HEATER CORE
10 - LOWER HVAC HOUSING
11 - HVAC WIRE HARNESS
12 - DRAIN FOAM SEAL
13 - BLOWER MOTOR
14 - EVAPORATOR FOAM SEAL
15 - EVAPORATOR
16 - HEATER CORE FOAM SEAL
DRDISTRIBUTION 24 - 35
HVAC HOUSING (Continued)