2002 CHRYSLER CARAVAN heater

(7) With the compressor clutch engaged, record the
left center panel outlet discharge air temperature,
the discharge pressure (high side service port), and
the suction pressure (low side service port). The com-
pressor clutch may cycle, depending upon the ambi-
ent temperature and humidity. If the clutch cycles,
use the readings obtained before the clutch disen-
gaged.
(8) Compare the discharge air temperature read-
ing to the Performance Temperature and Pressurechart. If the temperature reading is high, check the
refrigerant system for leaks and proper refrigerant
charge level. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - FRONT/REFRIGERANT -
DIAGNOSIS AND TESTING - REFRIGERANT SYS-
TEM LEAKS) and (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - FRONT/REFRIGER-
ANT - DIAGNOSIS AND TESTING - REFRIGER-
ANT SYSTEM CHARGE LEVEL).
Performance Temperature and Pressure
Ambient Temperature 21É C
(70É F)27É C
(80É F)32É C
(90É F)38É C
(100É F)43É C
(110É F)
Left Center Panel
Outlet Discharge Air
Temperature1to8ÉC
(34 to 46É F)3to9ÉC
(37 to 49É F)4 to 10ÉC
(39 to 50É F)6to11ÉC
(43 to 52É F)7 to 18É C
(45 to 65É F)
Discharge Pressure
(High Side Service
Port)1034 to 1724
kPa
(150 to 250
psi)1517 to 2275
kPa
(220 to 330
psi)1999 to 2620
kPa
(290 to 380
psi)2068 to 2965
kPa
(300 to 430
psi)2275 to 3421
kPa
(330 to 450 psi)
Suction Pressure (Low
Side Service Port)103 to 207 kPa
(15 to 30 psi)117 to 221 kPa
(17 to 32 psi)138 to 241 kPa
(20 to 35 psi)172 to 269 kPa
(25 to 39 psi)207 to 345 kPa
(30 to 50 psi)
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE TEST
PRE-DIAGNOSTIC PREPARATIONS
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING FRONT - WARNING - HEATER PLUMB-
ING).
Check the coolant level, drive belt tension, radiator
air flow, and cooling fan operation. Start the engine
and allow it to warm up to normal temperature.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system by
two 16 mm (5/8 inch inside diameter) heater hoses.
With the engine idling at normal running tempera-
ture, set the heater-A/C controls as follows. Temper-
ature control to full Heat, Mode control to Floor,
Blower control to the highest speed setting. Using a
test thermometer, check the air temperature coming
from the center floor outlets and compare this read-
ing to the Temperature Reference table.
TEMPERATURE REFERENCE
AMBIENT
TEMPERATUREMINIMUM FLOOR
OUTLET
TEMPERATURE
CELSIUS FAHRENHEIT CELSIUS FAHRENHEIT
15.5É 60É 62.2É 144É
21.1É 70É 63.8É 147É
26.6É 80É 65.5É 150É
32.2É 90É 67.2É 153É
If the floor outlet air temperature is insufficient,
check that the cooling system is operating to specifi-
cations. (Refer to 7 - COOLING/ENGINE - DIAGNO-
SIS AND TESTING). Both heater hoses should be
HOT to the touch (the coolant return hose should be
slightly cooler than the supply hose). If the coolant
return hose is much cooler than the supply hose,
locate and repair the engine coolant flow obstruction
in heater system.
POSSIBLE LOCATIONS OR CAUSE OF OBSTRUCTED
COOLANT FLOW
²Pinched or kinked heater hoses.
²Improper heater hose routing.
²Plugged heater hoses or supply and return ports
at cooling system connections.
²Plugged heater core.
²Air locked heater core.
²Restrictor in backwards.
24 - 6 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)
ProCarManuals.com

If coolant flow is verified and the heater floor out-
let temperature is insufficient, a mechanical problem
may exist.
POSSIBLE LOCATION OR CAUSE OF INSUFFICIENT HEAT
²Obstructed cowl air intake.
²Obstructed heater system outlets.
²Blend-air door not functioning properly.TEMPERATURE CONTROL
If heater floor outlet temperature cannot be
adjusted with the heater-A/C control temperature
control lever, one of the following could require ser-
vice:
²Blend-air door binding.
²Faulty blend-air door motor.
²Improper engine coolant temperature.
²Faulty heater-A/C control.
SPECIFICATIONS - HEATER-A/C SYSTEM
ITEM DESCRIPTION NOTES
Vehicle RS - Caravan, Town & Country, Voyager
System R134a with expansion valve(s)
Compressor Nippondenso - 10S20 ND-8 PAG Oil
Freeze±up Control evaporator temperature sensor expansion valve mounted - input
to heater-A/C control module
Low PSI Control liquid line mounted - input to
Powertrain Control Module (PCM)
- PCM opens compressor clutch
relay < 29.4 psi
High PSI Control pressure transducer liquid line mounted - input to
PCM - PCM opens compressor
clutch relay > 450 psi
pressure relief valve compressor mounted - opens >
495 psi
Control Head single zone, dual zone, and three zone
Manual Temperature Control (MTC) - or three
zone Automatic Temperature Control (ATC)PCI data bus messaging - ATC
uses three infrared temperature
sensors - two front/one rear
Mode Door electric actuator Control head driven
Blend Air Door electric actuator
Fresh/Recirc Door electric actuator
Blower Motor control head switch resistor and relay with MTC,
power module and relay with ATC
Cooling Fans pulse width modulated variable speed PCM control through solid state
fan relay
Clutch
Clutch Control PCM PCM control through compressor
clutch relay
Clutch Coil Draw 2.2 amps @ 12V   0.5amps@ 70É F
Compressor Clutch Air Gap 0.0209- 0.0359
Diagnostics DRBIIITscan tool
RSHEATING & AIR CONDITIONING24-7
HEATING & AIR CONDITIONING (Continued)
ProCarManuals.com

CONTROLS - FRONT
TABLE OF CONTENTS
page page
A/C HEATER CONTROL
STANDARD PROCEDURE - HEATER-A/C
CONTROL CALIBRATION................8
REMOVAL.............................9
INSTALLATION..........................9
A/C PRESSURE TRANSDUCER
DESCRIPTION - A/C PRESSURE
TRANSDUCER.......................10
OPERATION...........................10
DIAGNOSIS AND TESTING - A/C PRESSURE
TRANSDUCER.......................10
REMOVAL.............................11
INSTALLATION.........................11
BLEND DOOR ACTUATOR
DESCRIPTION.........................11
OPERATION...........................11
REMOVAL.............................12
INSTALLATION.........................12
BLOWER MOTOR RELAY
DESCRIPTION.........................13
OPERATION...........................13
DIAGNOSIS AND TESTING - BLOWER
MOTOR RELAY.......................14
REMOVAL.............................14
INSTALLATION.........................14
BLOWER MOTOR RESISTOR
DESCRIPTION.........................15
OPERATION...........................15
DIAGNOSIS AND TESTING - BLOWER
MOTOR RESISTOR....................15
REMOVAL.............................16
INSTALLATION.........................16
COMPRESSOR CLUTCH
DESCRIPTION.........................16
OPERATION...........................17
STANDARD PROCEDURE
STANDARD PROCEDURE - COMPRESSOR
CLUTCH AIR GAP.....................17STANDARD PROCEDURE - COMPRESSOR
CLUTCH BREAK-IN....................17
REMOVAL.............................17
INSPECTION - COMPRESSOR CLUTCH/COIL . 18
INSTALLATION.........................19
COMPRESSOR CLUTCH COIL
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH COIL........................20
COMPRESSOR CLUTCH RELAY
DESCRIPTION.........................21
OPERATION...........................21
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH RELAY......................22
REMOVAL.............................22
INSTALLATION.........................22
EVAPORATOR TEMPERATURE SENSOR
DESCRIPTION.........................22
OPERATION...........................23
REMOVAL.............................23
INSTALLATION.........................23
INFRARED TEMPERATURE SENSOR
DESCRIPTION.........................24
OPERATION...........................24
MODE DOOR ACTUATOR
DESCRIPTION.........................24
OPERATION...........................25
REMOVAL.............................25
INSTALLATION.........................25
POWER MODULE
DESCRIPTION.........................26
OPERATION...........................26
REMOVAL.............................26
INSTALLATION.........................27
RECIRCULATION DOOR ACTUATOR
DESCRIPTION.........................27
OPERATION...........................27
REMOVAL.............................28
INSTALLATION.........................28
A/C HEATER CONTROL
STANDARD PROCEDURE - HEATER-A/C
CONTROL CALIBRATION
The heater-A/C control module must be recali-
brated each time an actuator motor or the control
module is replaced. If the vehicle is so equipped, the
calibration procedure also includes rear HVAC posi-
tions for each actuator motor.(1) Turn the ignition switch to the On position.
(2) Simultaneously depress and hold the Power
and Recirculation buttons on the heater-A/C control
for at least five seconds. The manual heater-A/C con-
trol power Light Emitting Diode (LED) and Recircu-
lation LED, or the Automatic Temperature Control
(ATC) heater-A/C control Delay and Recirculation
graphics will begin to flash when the calibration pro-
cedure has begun.
24 - 8 CONTROLS - FRONTRS
ProCarManuals.com

(3) The calibration procedure should take less than
two minutes to complete for the manual heater-A/C
control, and less than twenty seconds for the ATC
heater-A/C control. When the LEDs or graphics stop
flashing, the calibration procedure is complete.
(4) If the LEDs or graphics continue to flash
beyond the normal three minute (manual) or twenty
second (ATC) calibration time, it indicates that the
heater-A/C control has detected a failure and a Diag-
nostic Trouble Code (DTC) has been set. Use a
DRBIIItscan tool to perform further diagnosis. Refer
to the appropriate diagnostic information. The LEDs
or graphics will continue to flash even after the igni-
tion switch is cycled Off and On, until a successful
calibration is completed or until the vehicle has been
driven about 13 kilometers (8 miles).
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 center bezel from the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - REMOV-
AL).
(3) Place the instrument panel center bezel unit
face down on a suitable work surface. Take the
proper precautions to protect the center bezel from
cosmetic damage.
(4) If the vehicle is equipped with the optional
Automatic Temperature Control (ATC) system, dis-
connect the infrared sensor jumper harness connector
from the receptacle on the back of the heater-A/C
control (Fig. 1).
(5) Remove the six screws that secure the heater-
A/C control to the back of the instrument panel cen-
ter bezel.
(6) Remove the heater-A/C control from the instru-
ment panel center bezel.
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 heater-A/C control onto the back of
instrument panel center bezel.
(2) Install and tighten the six screws that secure
the heater-A/C control to the back of the instrument
panel center bezel. Tighten the screws to 2 N´m (17
in. lbs.).
(3) If the vehicle is equipped with the optional
ATC system, reconnect the infrared sensor jumper
harness connector to the receptacle on the back of
the heater-A/C control.
(4) Reinstall the center bezel onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - INSTAL-
LATION).
(5) Reconnect the battery negative cable.
Fig. 1 Heater-A/C Control
1 - INFRARED SENSOR JUMPER CONNECTOR (ATC ONLY)
2 - INFRARED SENSOR JUMPER HARNESS (ATC ONLY)
3 - HEATER-A/C CONTROL
4 - SCREW (6)
5- INSTRUMENT PANEL CENTER BEZEL
RSCONTROLS - FRONT24-9
A/C HEATER CONTROL (Continued)
ProCarManuals.com

REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the headlamp and dash wire har-
ness connector for the A/C pressure transducer from
the transducer connector receptacle (Fig. 3).
(3) Using an open end wrench, unscrew the A/C
pressure transducer from the fitting on the liquid
line between the filter-drier and the expansion valve.
(4) Remove the seal from the A/C pressure trans-
ducer fitting and discard.
INSTALLATION
(1) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the A/C pressure
transducer fitting.
(2) Using an open end wrench, install and tighten
the A/C pressure transducer onto the fitting on the
liquid line between the filter-drier and the expansion
valve.
(3) Reconnect the headlamp and dash wire harness
connector for the A/C pressure transducer to the
transducer connector receptacle.
(4) Reconnect the battery negative cable.
BLEND DOOR ACTUATOR
DESCRIPTION
The blend door actuators are reversible, 12-volt
Direct Current (DC), servo motors. Models with the
single zone heater and air conditioner system have a
single blend air door, which is controlled by a singleblend door actuator. Models with the optional dual
zone front heater and air conditioner system have
dual blend air doors, which are controlled by two
blend door actuators. The single zone blend door
actuator is located on the driver side end of the heat-
er-A/C housing unit, close to the dash panel. In the
dual zone system, the same blend door actuator used
for the single zone system becomes the passenger
blend door actuator, and is mechanically connected to
only the passenger side blend air door. In the dual
zone system, a second separate blend door actuator is
also located on the driver side end of the heater-A/C
housing unit close to the instrument panel, and is
mechanically connected to only the driver side blend
air door.
The blend door actuators are interchangeable with
each other, as well as with the actuators for the
mode door and the recirculation air door. Each actua-
tor is contained within an identical black molded
plastic housing with an integral wire connector
receptacle. Two integral mounting tabs allow the
actuator to be secured with two screws to the heater-
A/C unit housing. Each actuator also has an identical
output shaft with splines that connects it to the link-
age that drives the proper blend air door. The blend
door actuators do not require mechanical indexing to
the blend door linkage, as they are electronically cal-
ibrated by the heater-A/C control module. The blend
door actuators cannot be adjusted or repaired and, if
damaged or faulty, they must be replaced.
OPERATION
Each blend door actuator is connected to the heat-
er-A/C control module through the vehicle electrical
system by a dedicated two-wire take out and connec-
tor of the HVAC wire harness. The blend door actua-
tor can move the blend air door in two directions.
When the heater-A/C control module pulls the volt-
age on one side of the motor connection high and the
other connection low, the blend air door will move in
one direction. When the module reverses the polarity
of the voltage to the motor, the blend air door moves
in the opposite direction. When the module makes
the voltage to both connections high or both connec-
tions low, the blend air door stops and will not move.
These same motor connections also provide a feed-
back signal to the heater-A/C control module. This
feedback signal allows the module to monitor the
operation and relative positions of the blend door
actuator and the blend air door. The heater-A/C con-
trol module learns the blend air door stop positions
during the calibration procedure and will store a
Diagnostic Trouble Code (DTC) for any problems it
detects in the blend door actuator circuits. The blend
door actuator can be diagnosed using a DRBIIItscan
tool. Refer to the appropriate diagnostic information.
Fig. 3 A/C Pressure Transducer
1 - RIGHT FRONT STRUT TOWER
2 - CONNECTOR
3 - A/C PRESSURE TRANSDUCER
4 - RIGHT WIPER MODULE DRAIN TUBE
5 - HIGH SIDE SERVICE PORT
6 - LIQUID LINE
RSCONTROLS - FRONT24-11
A/C PRESSURE TRANSDUCER (Continued)
ProCarManuals.com

REMOVAL
The single zone heating and air conditioning sys-
tem is equipped with a single blend door actuator.
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 pro-
cedures can be used for each of these actuators.
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 silencer from beneath the driver
side end of the instrument panel. (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL SILENCER - REMOVAL).
(3) Remove the three screws that secure the heater
core shield to the left end of the HVAC distribution
housing (Fig. 4).(4) Pull the heater core shield rearward far enough
to disengage the two location tabs that position the
front of the shield to the receptacles in the two lower
finger formations of the heater/ air conditioner hous-
ing near the dash panel.
(5) Remove the heater core shield from the distri-
bution housing.
(6) Disconnect the HVAC wire harness connector
for the blend door actuator from the actuator connec-
tor receptacle (Fig. 5).
(7) Remove the two screws that secure the blend
door actuator to the distribution housing.
(8) Remove the blend door actuator from the dis-
tribution housing.
INSTALLATION
(1) Position the blend door actuator onto the heat-
er/air conditioner housing. If necessary, rotate the
actuator slightly to align the splines on the actuator
output shaft with those in the blend air door linkage.
(2) Install and tighten the two screws that secure
the blend door actuator to the distribution housing.
Tighten the screws to 2 N´m (17 in. lbs.).
(3) Reconnect the HVAC wire harness connector
for the blend door actuator to the actuator connector
receptacle.
(4) Position the heater core shield onto the distri-
bution housing. Be certain that the two location tabs
on the front of the shield are engaged in the recepta-
cles in the two lower finger formations of the evapo-
rator housing near the dash panel.
Fig. 4 Heater Core Shield
1 - HEATER/ AIR CONDITIONER HOUSING
2 - HEATER CORE SHIELD
3 - DISTRIBUTION HOUSING
4 - SCREWS (3)
5 - LOCATION TABS (2)
Fig. 5 Blend Door Actuator
1 - CONNECTOR
2 - MODE DOOR ACTUATOR
3 - SCREW (2)
4 - DRIVER BLEND DOOR ACTUATOR (DUAL-ZONE ONLY)
5 - HEATER CORE
6 - BLEND DOOR ACTUATOR (SINGLE ZONE) OR PASSENGER
BLEND DOOR ACTUATOR (DUAL-ZONE)
24 - 12 CONTROLS - FRONTRS
BLEND DOOR ACTUATOR (Continued)
ProCarManuals.com

(5) Install and tighten the three screws that secure
the heater core shield to the left end of the heater/air
conditioner housing. Tighten the screws to 2 N´m (17
in. lbs.).
(6) Reinstall the silencer under the driver side end
of the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/INSTRUMENT PANEL
SILENCER - INSTALLATION).
(7) Reconnect the battery negative cable.
(8) 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).
BLOWER MOTOR RELAY
DESCRIPTION
The blower motor relay (Fig. 6) is a International
Standards Organization (ISO) mini-relay. Relays con-
forming to the ISO specifications have common phys-
ical dimensions, current capacities, terminal
patterns, and terminal functions. The ISO mini-relay
terminal functions are the same as a conventional
ISO relay. However, the ISO mini-relay terminal pat-
tern (or footprint) is different, the current capacity is
lower, and the physical dimensions are smaller than
those of the conventional ISO relay. The blower
motor relay is located in the Intelligent Power Mod-
ule (IPM), which is in the engine compartment near
the battery. See the fuse and relay layout mapmolded into the inner surface of the IPM cover for
blower motor relay identification and location.
The black, molded plastic case is the most visible
component of the blower motor relay. Five male
spade-type terminals extend from the bottom of the
base to connect the relay to the vehicle electrical sys-
tem, and the ISO designation for each terminal is
molded into the base adjacent to each terminal.
OPERATION
The blower motor relay is an electromechanical
switch that uses a low current input from the Front
Control Module (FCM) to control the high current
output to the blower motor resistor (manual heater-
A/C control) or blower power module (ATC control).
The movable common feed contact point is held
against the fixed normally closed contact point by
spring pressure. When the relay coil is energized, an
electromagnetic field is produced by the coil wind-
ings. This electromagnetic field draws the movable
relay contact point away from the fixed normally
closed contact point, and holds it against the fixed
normally open contact point. When the relay coil is
de-energized, spring pressure returns the movable
contact point back against the fixed normally closed
contact point. The resistor or diode is connected in
parallel with the relay coil in the relay, and helps to
dissipate voltage spikes and electromagnetic interfer-
ence that can be generated as the electromagnetic
field of the relay coil collapses.
The blower motor relay terminals are connected to
the vehicle electrical system through a receptacle in
the Intelligent Power Module (IPM). The inputs and
outputs of the blower motor relay include:
²The common feed terminal (30) receives a bat-
tery current input from the battery through a B(+)
circuit at all times.
²The coil ground terminal (85) receives a ground
input through the front/rear blower motor relay con-
trol circuit only when the FCM electronically pulls
the control circuit to ground.
²The coil battery terminal (86) receives a battery
current input from the battery through a B(+) circuit
at all times.
²The normally open terminal (87) provides a bat-
tery current output to the blower motor resistor
(manual heater-A/C control) or blower power module
(automatic heater-A/C control) through a fuse in the
IPM on the fused front blower motor relay output cir-
cuit only when the blower motor relay coil is ener-
gized.
²The normally closed terminal (87A) is not con-
nected to any circuit in this application, but provides
a battery current output only when the blower motor
relay coil is de-energized.
Fig. 6 Blower Motor Relay
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
RSCONTROLS - FRONT24-13
BLEND DOOR ACTUATOR (Continued)
ProCarManuals.com

BLOWER MOTOR RESISTOR
DESCRIPTION
A blower motor resistor is used on this model when
it is equipped with the manual heater-A/C control
(Fig. 9). Models equipped with the optional Auto-
matic Temperature Control (ATC) use a blower power
module, instead of the blower motor resistor. The
blower motor resistor is installed in a mounting hole
in the heater/AC housing, directly behind the glove
box opening of the instrument panel. The resistor
consists of a molded plastic mounting plate with two
integral connector receptacles. Concealed behind the
mounting plate within the heater/AC housing are
four coiled resistor wires contained within a protec-
tive stamped steel cage. The resistor mounting plate
is secured with two screws to the heater/AC housing
and is accessed for service by rolling down the glove
box from the instrument panel.
The blower motor resistor wires will get hot when
in use. Do not touch the resistor wires or the protec-
tive cage if the blower motor has been running. The
blower motor resistor cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced.
OPERATION
The blower motor resistor is connected to the vehi-
cle electrical system through a dedicated take out
and connector of the instrument panel wire harness.
A second connector receptacle receives the pigtail
wire connector from the blower motor. The blower
motor resistor has multiple resistor wires, each ofwhich will reduce the current flow through the
blower motor to change the blower motor speed. The
blower motor switch in the manual heater-A/C con-
trol directs the ground path for the blower motor
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 resistor wires, increasing the blower motor
speed. When the blower motor switch is in the high-
est speed position, the blower motor resistor wires
are bypassed and the blower motor receives a direct
path to ground through the blower motor switch. The
blower motor resistor may be diagnosed using con-
ventional diagnostic tools and methods.
DIAGNOSIS AND TESTING - BLOWER MOTOR
RESISTOR
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
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) Disconnect the instrument panel wire harness
connector for the blower motor resistor and the
blower motor pigtail wire connector from the resistor
connector receptacles.
(3) Check for continuity between each of the
blower motor switch input terminals of the blower
motor resistor and the resistor output terminal. In
each case there should be continuity. If OK, repair
the instrument panel wire harness circuits between
the blower motor switch and the blower motor resis-
tor or the blower motor pigtail wires as required. If
not OK, replace the faulty blower motor resistor.
Fig. 9 Blower Motor Resistor
1 - BLOWER MOTOR RESISTOR
2 - INSTRUMENT PANEL WIRE HARNESS
3 - SCREW (2)
4 - GLOVE BOX OPENING LOWER REINFORCEMENT
5 - BLOWER MOTOR PIGTAIL WIRE
6 - EVAPORATOR HOUSING
RSCONTROLS - FRONT24-15
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