2003 CHRYSLER CARAVAN low oil pressure

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 Pressure transducer 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
Automatic Temperature Control (ATC), (Two
or Three Zone)PCI data bus messaging - ATC
uses two infrared temperature
sensors
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)
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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.............................10
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.........................14
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.........................23
OPERATION...........................24
MODE DOOR ACTUATOR
DESCRIPTION.........................24
OPERATION...........................24
REMOVAL.............................25
INSTALLATION.........................25
POWER MODULE
DESCRIPTION.........................25
OPERATION...........................26
REMOVAL.............................26
INSTALLATION.........................26
RECIRCULATION DOOR ACTUATOR
DESCRIPTION.........................27
OPERATION...........................27
REMOVAL.............................27
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
24 - 8 CONTROLS - FRONTRS
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(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 single
blend door actuator. Models with the optional dual
zone front heater and air conditioner system have
dual blend air doors, which are controlled by twoblend 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)
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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 map
molded 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.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, further details
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)
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damaged, the clutch electromagnetic coil unit must
be replaced.
OPERATION
The compressor clutch components provide the
means to engage and disengage the compressor from
the engine serpentine accessory drive belt. When the
clutch coil is energized, it magnetically draws the
clutch plate into contact with the clutch pulley and
drives the compressor shaft. When the coil is not
energized, the pulley freewheels on the clutch hub
bearing, which is part of the pulley.
A zener diode is connected in parallel with the
clutch electromagnetic coil. This diode controls the
dissipation of voltage induced into the coil windings
by the collapsing of the electromagnetic fields that
occurs when the compressor clutch is disengaged.
The zener diode dissipates this induced voltage by
regulating a current path to ground. This arrange-
ment serves to protect other circuits and components
from potentially damaging voltage spikes in the vehi-
cle electrical system that might occur if the voltage
induced in the clutch coil windings could not be dis-
sipated.
The compressor clutch engagement is controlled by
several components: the heater-A/C controls in the
passenger compartment, the A/C pressure transducer
on the liquid line, the evaporator temperature sensor
on the expansion valve, the Powertrain Control Mod-
ule (PCM) in the engine compartment, and the com-
pressor clutch relay in the Intelligent Power Module
(IPM). The PCM may delay compressor clutch
engagement for up to thirty seconds. (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-ULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION - PCM OPERATION).
STANDARD PROCEDURE
STANDARD PROCEDURE - COMPRESSOR
CLUTCH AIR GAP
If a new clutch plate and/or clutch pulley are being
used, the air gap between the clutch plate and clutch
pulley must be checked using the following proce-
dure:
(1) Using feeler gauges, measure the air gap
between the clutch plate and the clutch pulley fric-
tion surfaces.
(2) If the air gap is not between 0.5 and 0.9 mm
(0.020 and 0.035 in.), add or subtract shims until the
desired air gap is obtained.
NOTE: The shims may compress after tightening
the compressor shaft bolt. Check the air gap in four
or more places on the clutch plate to verify that the
air gap is still correct. Spin the clutch pulley before
making the final air gap check.
STANDARD PROCEDURE - COMPRESSOR
CLUTCH BREAK-IN
After a new compressor clutch has been installed,
check that the compressor clutch coil is performing to
specifications. (Refer to 24 - HEATING & AIR CON-
DITIONING/CONTROLS - FRONT/COMPRESSOR
CLUTCH COIL - DIAGNOSIS AND TESTING). If
the clutch coil is performing to specifications, per-
form the compressor clutch break-in procedure. This
procedure (burnishing) will seat the opposing friction
surfaces and provide a higher compressor clutch
torque capability.
(1) Set the heater-A/C controls to the A/C mode,
with the blower switch in the highest speed position.
(2) Start the engine and hold the engine speed at
1500 to 2000 rpm.
(3) Cycle the compressor clutch On and Off about
twenty times (seven seconds On, then seven seconds
Off).
REMOVAL
The refrigerant system can remain fully charged
during compressor clutch, pulley, or coil replacement.
Although the compressor assembly must be removed
from its mounting, the compressor clutch can be ser-
vice with the compressor in the vehicle.
(1) Disconnect and isolate the battery negative
cable.
(2) Raise and support the vehicle.
Fig. 11 Compressor Clutch - Typical
1 - CLUTCH PLATE
2 - SHAFT KEY (SOME MODELS)
3 - PULLEY AND BEARING
4 - CLUTCH COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
RSCONTROLS - FRONT24-17
COMPRESSOR CLUTCH (Continued)
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(5) Using snap ring pliers (Special Tool C-4574 or
equivalent), install the external snap ring (bevel side
facing outward) that secures the clutch pulley to the
front cover of the compressor. Be certain that the
snap ring is fully and properly seated in the groove.
(6) If the original clutch plate and clutch pulley
are to be reused, reinstall the original shim(s) on the
compressor shaft against the shoulder. If a new
clutch plate and/or clutch pulley are being used,
install a trial stack of shims 1.0 mm (0.040 in.) thick
on the compressor shaft against the shoulder.
(7) Install the clutch plate onto the compressor
shaft.
(8) Install and tighten the compressor shaft nut. If
necessary, a band-type oil filter wrench or a strap
wrench can be placed around the clutch plate to aid
in bolt tightening. Tighten the bolt to 17.5 N´m (155
in. lbs.).
(9) If a new clutch plate and/or clutch pulley are
being installed, the air gap between the clutch plate
and clutch pulley must be checked. (Refer to 24 -
HEATING & AIR CONDITIONING/CONTROLS -
FRONT/COMPRESSOR CLUTCH - STANDARD
PROCEDURE - COMPRESSOR CLUTCH AIR GAP).
(10) On models with the 2.4L engine only, loosely
install the four screws that secure the compressor to
the mounting bracket on the engine. Tighten the
screws to 28 N´m (21 ft. lbs.).
(11) On models with the 3.3L and 3.8L engines
only, loosely install the two screws and two nuts that
secure the compressor to the engine. Tighten each ofthe fasteners using the following sequence to 54 N´m
(40 ft. lbs.).
²The upper nut at the front of the compressor.
²The lower nut at the front of the compressor.
²The upper screw at the rear of the compressor.
²The lower screw at the rear of the compressor.
(12) On models with the 3.3L and 3.8L engines
only, engage the retainer on the engine wire harness
compressor clutch coil take out with the bracket on
the top of the compressor.
(13) Reconnect the engine wire harness connector
for the compressor clutch coil to the coil pigtail wire
connector on the top of the compressor.
(14) Reinstall the serpentine accessory drive belt
onto the front of the engine. (Refer to 7 - COOLING/
ACCESSORY DRIVE/DRIVE BELTS - 2.4L -
INSTALLATION) or (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - 3.3L/3.8L - INSTAL-
LATION).
(15) Lower the vehicle.
(16) Reconnect the battery negative cable.
(17) If a new clutch plate and/or clutch pulley are
being installed, the new clutch components must be
burnished. (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS - FRONT/COMPRESSOR
CLUTCH - STANDARD PROCEDURE - COMPRES-
SOR CLUTCH BREAK-IN).
COMPRESSOR CLUTCH COIL
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH COIL
The air conditioning compressor clutch coil electri-
cal circuit is controlled by the Powertrain Control
Module (PCM) through the compressor clutch relay,
which is located in the Intelligent Power Module
(IPM) in the engine compartment near the battery.
Begin testing of a suspected compressor clutch coil
problem by performing the preliminary checks.
PRELIMINARY CHECKS
(1) If the compressor clutch will not engage, verify
the refrigerant charge level. (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING - FRONT/RE-
FRIGERANT - DIAGNOSIS AND TESTING -
REFRIGERANT CHARGE LEVEL). If the refriger-
ant charge level is OK, go to Step 2. If the refriger-
ant charge level is not OK, adjust the refrigerant
charge as required.
(2) If the a/c compressor clutch still will not
engage, disconnect the headlamp and dash wire har-
ness connector for the A/C pressure transducer and
check for battery current at the connector with the
engine running and the heater-A/C control set to the
A/C mode. If OK, go to TESTS . If not OK, use a
Fig. 16 Install Clutch Pulley
1 - PULLEY ASSEMBLY
2 - WOOD BLOCK
24 - 20 CONTROLS - FRONTRS
COMPRESSOR CLUTCH (Continued)
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DRBIIItscan tool to perform further diagnosis. Refer
to the appropriate diagnostic information.
TESTS
(1) Verify the battery state of charge. (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM/BATTERY -
DIAGNOSIS AND TESTING).
(2) Connect an ammeter (0 to 10 ampere scale
selected) in series with the clutch coil feed terminal.
Connect a voltmeter (0 to 20 volt scale selected) to
measure voltage across the battery and the clutch
coil.
(3) With the heater-A/C control in the A/C mode
and the blower at low speed, start the engine and
allow it to run at a normal idle speed.
(4) The compressor clutch should engage immedi-
ately, and the clutch coil voltage should be within
two volts of the battery voltage. If the coil voltage is
not within two volts of battery voltage, test the
clutch coil feed circuit for excessive voltage drop. If
the compressor clutch does not engage, use a
DRBIIItscan tool to perform further diagnosis. Refer
to the appropriate diagnostic information.
(5) With the ambient temperature at 21É C (70É F),
the compressor clutch coil is acceptable if the current
draw is 2.0 to 3.7 amperes at 11.5 to 12.5 volts at the
clutch coil. If the voltage is more than 12.5 volts, add
electrical loads by turning on electrical accessories
until the voltage reads below 12.5 volts.
(a) If the compressor clutch coil current reading
is zero, the coil is open and must be replaced.
(b) If the compressor clutch coil current reading
is four amperes or more, the coil is shorted and
must be replaced.
COMPRESSOR CLUTCH RELAY
DESCRIPTION
The compressor clutch relay (Fig. 17) is a Interna-
tional Standards Organization (ISO) micro-relay.
Relays conforming to the ISO specifications have
common physical dimensions, current capacities, ter-
minal patterns, and terminal functions. The ISO
micro-relay terminal functions are the same as a con-
ventional ISO relay. However, the ISO micro-relay
terminal pattern (or footprint) is different, the cur-
rent capacity is lower, and the physical dimensions
are smaller than those of the conventional ISO relay.
The compressor clutch relay is located in the Intelli-
gent Power Module (IPM), which is in the engine
compartment near the battery. See the fuse and relay
layout map molded into the inner surface of the IPM
cover for compressor clutch relay identification and
location.The black, molded plastic case is the most visible
component of the compressor clutch 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 compressor clutch relay is an electromechani-
cal switch that uses a low current input from the
Powertrain Control Module (PCM) to control the high
current output to the compressor clutch electromag-
netic coil. 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 compressor clutch relay terminals are con-
nected to the vehicle electrical system through a
receptacle in the Intelligent Power Module (IPM).
The inputs and outputs of the compressor clutch
relay include:
²The common feed terminal (30) receives a bat-
tery current input from a fuse in the IPM through a
fused B(+) circuit at all times.
²The coil ground terminal (85) receives a ground
input from the PCM through the compressor clutch
relay control circuit only when the PCM electroni-
cally pulls the control circuit to ground.
²The coil battery terminal (86) receives a battery
current input from the PCM through a fused ignition
switch output (run-start) circuit only when the igni-
tion switch is in the On or Start positions.
²The normally open terminal (87) provides a bat-
tery current output to the compressor clutch coil
through the compressor clutch relay output circuit
only when the compressor clutch 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 compressor
clutch relay coil is de-energized.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, further details
on wire harness routing and retention, as well as
RSCONTROLS - FRONT24-21
COMPRESSOR CLUTCH COIL (Continued)
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(9) Reinstall the right quarter trim panel and
right D-pillar trim panel onto the quarter inner
panel. (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).
(10) Reconnect the battery negative cable.
(11) Perform the heater-A/C control calibration
procedure. (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS - FRONT/A/C-HEATER CON-
TROL - STANDARD PROCEDURE - HEATER-A/C
CONTROL CALIBRATION).
BLOWER MOTOR RELAY
DESCRIPTION
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
The blower motor relay (Fig. 5) 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
compressor clutch 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. The
ISO terminal designations are as follows:
²30 (Common Feed)- This terminal is con-
nected to the movable contact point of the relay.
²85 (Coil Ground)- This terminal is connected
to the ground feed side of the relay control coil.
²86 (Coil Battery)- This terminal is connected
to the battery feed side of the relay control coil.
²87 (Normally Open)- This terminal is con-
nected to the normally open fixed contact point of the
relay.
²87A (Normally Closed)- This terminal is con-
nected to the normally closed fixed contact point of
the relay.
The factory-installed blower motor relay cannot be
adjusted or repaired. If the relay is damaged or
faulty, it must be replaced.
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 (automatic heat-
er-A/C control). The movable common feed contact
point is held against the fixed normally closed con-
tact point by spring pressure. When the relay coil is
energized, an electromagnetic field is produced by the
coil windings. This electromagnetic field draws the
movable relay contact point away from the fixed nor-
mally closed contact point, and holds it against the
fixed normally open contact point. When the relay
coil is de-energized, spring pressure returns the mov-
able contact point back against the fixed normally
closed contact point. The resistor or diode is con-
nected in parallel with the relay coil in the relay, and
helps to dissipate voltage spikes and electromagnetic
interference that can be generated as the electromag-
netic 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 compressor clutch 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-
Fig. 5 Blower Motor Relay
24 - 32 CONTROLS - REARRS
BLEND DOOR ACTUATOR (Continued)
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