2001 CHRYSLER VOYAGER ignition

Front and rear blower relay
The blower control switch is part of the Automatic
Temperature Control (ATC) or A/C-Heater Control
Module, (Manual Temp). When the blower switch is
turned on, the ATC or A/C-Heater Control Module
sends a PCI Bus message to the FCM. The front and
rear blower relay is then powered through low side
control on pin 30 of the FCM. The relay provides the
high side to the blower motor, and the blower speed
is governed through low side control in the ATC or
A/C-Heater Control Module. This circuit is electron-
ically controlled and continuously monitored for
malfunctions.
Name Brand Speakers (NBS) relay
The NBS relay operates through the vehicle bus
interface between the radio and the FCM. When the
radio is turned on, the radio sends a PCI Bus
message to the FCM. The NBS relay is then pow-
ered on through low side control on pin 11 of the
FCM. The relay supplies power to the amplified
speaker, and ground is supplied through the radio.
This circuit is electronically controlled and contin-
uously monitored for malfunctions.
Electronic Back Light (EBL) relay
The rear defrost switch is part of the Automatic
Temperature Control or A/C-Heater Control Module
(Manual Temp). When the ignition switch is in the
RUN position and the rear defrost switch is turned
on, the ATC or A/C-Heater Control Module sends a
PCI Bus message to the FCM. The EBL run only
relay is then powered through low side control on
pin 31 of the FCM. The relay provides the high side
to the rear window defrost grid, and ground is
attached to the vehicle body. The FCM will only
allow the rear defrost to operate in the RUN posi-
tion. This circuit is electronically controlled and
continuously monitored for malfunctions.
Cabin Heater Relay
When the ignition is in Run, the FCM monitors
the PCI bus for the Cabin Heater Activation re-
quest. The A/C ± Heater Control Module initiates
this request only when all conditions for Cabin
Heater activation are favorable. The request carries
the status bit that the FCM requires to activate its
Cabin Heater Assist Control output. This output is
a low side driver (coming from FCM pin 15) which
supplies a ground signal to the Cabin Heater (pin
5). When the Cabin Heater receives this ground
signal input, it interprets this as an activation
signal. The FCM low side driver is also capable of
diagnostic sensing. The driver will sense an open
circuit when the driver is off, and will sense a short
to voltage when the driver is on. The FCM will set
DTCs for both of these types of faults. For addi-
tional information, refer to Cabin Heater under
General Information and Diagnostic Procedures in
the manual.3.8.3 ELECTRICAL INPUTS
Headlamp battery supplies1&2Ð12 volt
input on pins 1 and 2. Battery supply voltage for
switching headlamp circuits only.
Module battery supply Ð12 volt input on pin 9.
Battery supply voltage for all other FCM opera-
tions.
Power ground ÐGround source on pin 8 for all
FCM operations.
Ignition switch RUN or START position status
Ð12 volt input on pin 37. Allows the FCM to
determine the ignition switch status for related
FCM operations.
Ignition switch START only status Ð12 volt
input on pin 19. Allows the FCM to discriminate
between RUN/START input and START for related
FCM operations.
PCI Bus ÐApproximately 7.5 volt input on pin 22.
Allows the FCM to communicate with other mod-
ules on the vehicle bus.
Stop lamp Switch status Ð12 volt input on pin
44. Provides for brake shift interlock function.
Horn Switch ÐGround input on pin 17. Primary
means for engaging the horn.
Back-up switch ÐGround input on pin 39. Input
is converted to a PCI Bus status message for use by
other modules.
Wiper park switch ÐGround input on pin 16.
Used to determine park placement of wipers. Also
used as feedback to FCM to determine correct
operating mode of wipers.
Washer fluid level switch ÐGround input to
pull-up on pin 18. Ground is switched into the
circuit when washer bottle fluid level is low.
Brake fluid level switch ÐGround input to
pull-up on pin 36. Ground is switched into the
circuit when brake fluid level is low.
Ambient temperature sensor ÐResistive input
to pull-up on pin 25. Corresponding voltage level is
converted to a PCI Bus message for use by other
modules on the bus.
Right park lamp outage Ð12 volt input on pin
21. Used to determine if right park lamp circuit is
operating properly.
Left park lamp outage Ð12 volt input on pin 41.
Used to determine if left park lamp circuit is
operating properly.
Battery IOD Ð12 volt input on pin 20. The FCM
enters a low power consumption mode when the
ignition is turned OFF. This low current draw
battery supply keeps the microprocessor function-
ing in the low power mode.
Battery (+) connection detection Ð12 volt
input on pin 38. The battery connection on the PDC
incorporates the use of an internal switch to deter-
mine if the connector is properly mated and the
Connector Positive Assurance (CPA) is engaged. If
15
GENERAL INFORMATION

The DCHA assembly consists of a:
²combustion air fan assembly
²burner housing
²burner insert
²control unit/heat exchanger
²combustion chamber
²dosing pump
3.10.2.2 COMBUSTION AIR FAN
The combustion air fan assembly includes the:
²combustion air fan
²combustion air fan inlet
²fuel supply inlet
The combustion air fan delivers the air required
for combustion from the combustion air inlet to the
burner insert.
3.10.2.3 BURNER HOUSING
The burner housing includes the:
²coolant inlet
²coolant outlet
²exhaust outlet
The burner housing accommodates the burner
insert and is combined with the control unit/heat
exchanger as an assembly.
3.10.2.4 BURNER INSERT
The burner insert includes the:
²combustion pipe fuel cross section
²glow plug/flame sensor
Inside the burner insert fuel is distributed across
the combustion pipe fuel cross section. Combustion
of the fuel/air mixture takes place within the com-
bustion pipe to heat the exchanger. The glow plug/
flame sensor located in the burner insert ignites the
fuel/air mixture during heater start up. After heater
start up, the glow plug/flame sensor operates in the
flame sensor function. The glow plug/flame sensor
designed as an electrical resistor is located in the
burner insert opposite the flame side.
3.10.2.5 CONTROL UNIT/HEAT
EXCHANGER
The control unit/heat exchanger includes the:
²control unit
²temperature sensor
²overheat protection
²heat exchanger
²connector terminal
The control unit controls and monitors combus-
tion operation. The control unit is ventilated bymeans of a ventilation hose routed from the com-
bustion air collector compartment of the burner.
The heat exchanger transfers the heat generated by
combustion to the coolant circuit. The control unit/
heat exchanger and the burner housing are an
assembly and must not be disassembled.
The temperature sensor senses the coolant tem-
perature in the heat exchanger as an electrical
resistance. This signal is sent to the control unit for
processing.
The overheat protection, controlled by the tem-
perature resistor, protects the heater against undue
operating temperatures. The overheat protection
will switch the heater off if the water temperature
exceeds 105ÉC (221ÉF).
3.10.2.6 DOSING PUMP
The dosing pump is a combined delivery, dosing,
and shut-off system for the fuel supply of the heater.
The dosing pump receives its supply of fuel from the
vehicle's fuel tank.
3.10.3 OPERATION
3.10.3.1 ACTIVATION
When the ignition is in Run, the FCM monitors
the PCI bus for the Cabin Heater Activation re-
quest. The A/C ± Heater Control Module initiates
this request only when all conditions for Cabin
Heater activation are favorable (see below). The
request carries the status bit that the FCM requires
to activate its Cabin Heater Assist Control Output.
This output is a low side driver (coming from FCM
pin 15) which supplies a ground signal to the Cabin
Heater (pin 5). When the Cabin Heater receives this
ground signal input, it interprets this as an activa-
tion signal. The FCM low side driver is also capable
of diagnostic sensing. The driver will sense an open
circuit when the driver is off, and will sense a short
to voltage when the driver is on. The FCM will set
DTCs for both of these types of faults.
The DCHA will activate only when the:
²engine is running.
²coolant temperature is below 66ÉC (151ÉF).
²fuel tank has greater than 1/8 of a tank of fuel.
²Power switch on the A/C ± Heater Control Module
is on.
²Blend Control on the A/C ± Heater Control Mod-
ule is set above 95% reheat.
²Front Control Module (FCM) sees the Cabin
Heater Activation request that is bussed from the
A/C ± Heater Control Module.
When the DCHA starting sequence begins, the
glow plug and the combustion air fan are activated.
After 30 seconds, the fuel dosing pump begins oper-
20
GENERAL INFORMATION

ating and the combustion air fan operation is sus-
pended for 3 seconds. Subsequently, the combustion
air fan speed is increased in two ramps within 56
seconds to nearly full load operation. After a stabi-
lization phase of 15 seconds, the combustion air fan
speed is again increased in a ramp within 50
seconds to nearly full load. After reaching full load
fuel delivery, the glow plug is deactivated and the
combustion air fan operation is increased to full
load. During the subsequent 45 seconds, as well as
in normal operation, the glow plug functions as a
flame sensor to monitor the flame condition. After
all these events, the automatically controlled heat-
ing operation starts.
In case of a no flame or a flame out condition, a
restart is automatically initiated. If the no flame
condition persists, fuel delivery is stopped and the
heater enters an error lockout mode with a run-
down of the combustion air fan. This will set one or
more DTCs in the DCHA Control's memory. If six
continuous attempts to start the heater fail due to
one or more faults in the DCHA system, the heater
enters a heater lockout mode. This will set DTC
B1813 along with any other fault(s) that the DCHA
Control identified.
3.10.3.2 HEATING
During the automatically controlled heating op-
eration, when the coolant temperature reaches
72ÉC (162ÉF), the heater will switch to a part load
operation. When the coolant temperature reaches
75ÉC (167ÉF) or if the heater runs for longer than 76
minutes the heater will switch to a control idle
period. If the coolant temperature drops to 71ÉC
(160ÉF) during a control idle period, the heater will
perform a regular starting sequence into full load
operation. A drop in coolant temperature to 65ÉC
(149ÉF) during part load operation will cause the
heater to switch to a full load operation.
3.10.3.3 DEACTIVATION
The DCHA will deactivate if the:
²engine is turned off.
²coolant temperature reaches 75ÉC (167ÉF).
²heater runs longer than 76 minutes.
²fuel tank has less than 1/8 of a tank of fuel.
²Power switch on the A/C ± Heater Control Module
is off.
²Blend Control on the A/C ± Heater Control Mod-
ule is set below 75% reheat.
When the heater is deactivated, the combustion
stops and a run-down sequence begins. During the
run-down sequence, the combustion air fan contin-
ues operation to cool down the heater. The fan is
automatically switched off after the run-down se-
quence is complete. The run-down time and thecombustion air fan speed depend on the heater
operating condition at the time of deactivation.
Run-down time is approximately 175 seconds when
deactivated in full load operation and approxi-
mately 100 seconds when deactivated in part load
operation.
3.10.4 DIAGNOSTICS
The DCHA is fully addressable with the DRBIIIt.
System tests include a Field Mode Test to activate
the DCHA for diagnostic testing purposes. The
DCHA Control will store up to three DTCs in its
memory. If the Controller detects a new fault in the
DCHA system, one that is not already stored in its
memory, it will clear the oldest of the three stored
DTCs, and it will store the new fault's DTC. If the
Controller detects a reoccurrence of a stored fault, it
will overwrite that fault's DTC with the most recent
occurrence.
3.11 INSTRUMENT CLUSTER
The Instrument Cluster receives and sends mes-
sages to other modules via the PCI bus circuit. The
indicator lamps will illuminate briefly for a bulb
check when the ignition is turned from off to run.
All of the gauges receive their information via the
PCI bus from the powertrain control module and
body control module.
The gauges and the LEDs are not individually
replaceable thereby requiring complete replace-
ment of the Instrument Cluster if a repair is neces-
sary. In the event that the Instrument Cluster loses
communication with other modules on the PCI bus,
the cluster will display ªno busº in the VF display.
The Trip/Reset button is used to switch the dis-
play from trip to total mileage. Holding the button
when the display is in the trip mode will reset the
trip mileage. This button is also used to put the
cluster in self-diagnostic mode. The odometer dis-
play uses blue-green vacuum fluorescent digital
characters.
On base vehicles, the Instrument Cluster has
three gauges: Speedometer, Fuel and Engine Cool-
ant Temperature. A red dot moves transversely
through openings in the Instrument Cluster face
(P-R-N-D-2-1) to indicate the gear selected.
With all other models, the Instrument Cluster
also includes a Tachometer and uses a vacuum-
fluorescent shift indicator.
The odometer display and door/liftgate ajar indi-
cators turn on when a door is opened to assist both
the customer and service technician to view the
odometer without turning the ignition on.
21
GENERAL INFORMATION

On vehicles equipped with AutoStick, the display
includes an O/D OFF indicator that is illuminated
when the driver presses the Overdrive Off button
on the transaxle shifter.
3.11.1 INSTRUMENT CLUSTER SELF TEST
1. Depress and hold the Odometer Reset button.
2. Turn the ignition switch to the RUN/START
position.
3. Release the Odometer reset button.
The Instrument Cluster will illuminate all indi-
cators and step the gauges through several calibra-
tion points. Also, the odometer will display any
stored codes that may have set.
3.11.2 MESSAGE CENTER
The Message Center is located above the brow of
the Instrument Cluster. It houses the following
warning indicators: Check Engine/Service Engine
Soon, high beam, left and right turn signals, Secu-
rity Alarm Set, and low oil pressure. On base
models equipped with the three-speed transaxle,
these indicators appear in the face of the cluster.
The Security Alarm set indicator is a red circle.
Activation of Instrument Cluster indicators is
coordinated with indicators in the message center
and EVIC to avoid redundancy. A revised safety
standard now requires that the seat belt warning
lamp in the Instrument Cluster remain lit if the
driver seat belt is not buckled. A headlamp out ISO
indicator has been added to the Instrument Cluster
to alert the driver when a headlamp is not function-
ing.
3.12 INTERIOR LIGHTING
3.12.1 COURTESY LAMP CONTROL
The body controller has direct control over all of
the vehicle's courtesy lamps. The body computer
will illuminate the courtesy lamps under any of the
following conditions:
1. Any door ajar and courtesy lamp switch on the
headlamp switch is not in the dome off position.
2. The courtesy lamp switch on the headlamp
switch is in the dome on position.
3. A Remote Keyless Entry unlock message is re-
ceived.
4. Driver door unlocked with key (with VTSS only).
3.12.2 ILLUMINATED ENTRY
Illuminated entry will be initiated when the cus-
tomer enters the vehicle by unlocking the doors
with the key fob, or with the key if the vehicle is
equipped with vehicle theft alarm. Upon exiting thevehicle, if the lock button is pressed with a door
open, illuminated entry will cancel when the door
closes. If the doors are closed and the ignition
switch is turned on, the illuminated entry also
cancels. The illuminated entry feature will not
operate if the courtesy lamp switch is in the dome
off position.
3.12.3 INTERIOR LIGHTING BATTERY
SAVER
If any of the interior lamps are left on after the
ignition is turned off, the BCM will turn them off
after 8 minutes. To return to normal operation, the
courtesy lamps will operate after the dome lamp
switch or door ajar switch changes state. The glove
box and switched reading lamps require that the
ignition be turned to the on/acc position.
3.13 MEMORY SYSTEM
The memory system consists of power driver 's
seat, power mirrors and radio presets. The Memory
Seat/Mirror Module (MSMM) is located under the
driver 's seat. It receives input from the following:
driver 's manual 8-way seat switch, driver 's seat
position sensors, PCI bus circuits, and the power
mirror sensors. The module uses these inputs to
perform the following functions: position the driv-
er 's memory seat, both exterior mirrors (during
recalls), and send/receive the memory system infor-
mation over the PCI bus.
The Memory Set Switch is wired to the Body
Control Module (BCM). When a button (either #1 or
#2) is pressed on the set switch causes the to BCM
send a message to the MSMM which in turn sends
a motion status messages to the BCM. If the BCM
receives no motion from the MSMM it will send a
recall message to the MSMM and radio (once igni-
tion is in run or accessory). The MSMM will in turn
position the drivers seat, both mirrors along with
recalling the radio presets. If the drivers seat or
either exterior mirror is inoperative from its own
respective switches, use the service information
and schematic to diagnose the problem. This man-
ual addresses the memory problems only and it is
assumed there is not a basic component failure.
3.13.1 POWER SEAT
The memory power seat provides the driver with
2 position settings for the driver 's seat. Each power
seat motor is connected to the MSMM with two
motor drive circuits. Each circuit is switched be-
tween battery and ground. By being able to bi-
directionally drive the circuits, the MSMM controls
the movement of the motors based on input from
the power seat switch or from the position sensors
when performing a memory recall. Each motor
22
GENERAL INFORMATION

seconds instead of 5, the CMTC will set the
variance to 8 and enter the fast calibration
mode.
3. The VAR light will come on and the last variance
setting will be displayed.
4. Press the STEP button to set the zone number.
5. Press the US/M button and resume normal op-
eration.
NOTE: Do not attach any magnetic device
such as a magnetic CB antenna to the
vehicle. This can cause the compass to give
false readings.
3.15 POWER DOOR LOCK SYSTEM
When the BCM receives input for a lock request
from a door lock switch, RKE or cylinder lock switch
(only with VTSS), it will turn the lock driver on for
a specified time of 375 msec. If the request is there
beyond 375 msec, the BCM considers the door lock
signal stuck. Once a door lock or unlock signal is
stuck for longer than 10 seconds, the BCM will set
a trouble code and the signal input is ignored until
the stuck condition disappears. The door lock
switches provide a variable amount of resistance
thereby dropping the voltage of the multiplexed
(MUX) circuit and the BCM will respond to that
command.
3.15.1 SLIDING DOOR MEMORY LOCK
When the BCM receives an input for a lock
request and a sliding door is open, the BCM will
turn on the lock driver as described above, and will
turn it on again when all sliding doors are closed.
NOTE: If the BCM receives an unlock input before
a sliding door is closed, this will cancel the memory
lock.
3.15.2 DOOR LOCK INHIBIT
When the key is in the ignition and in any
position and either front door is open, the door lock
switches LOCK functions are disabled. The UN-
LOCK functions are still functional. This protects
against locking the vehicle with the keys still in the
ignition. The RKE key fob will still lock the doors as
usual. This allows the driver to lock the vehicle with
the engine running for warm up.
3.15.3 AUTOMATIC DOOR LOCKS
This feature can be enabled or disabled by using
either the DRBIIItor the customer programming
method. When enabled all the doors will lock when
the vehicle reaches a speed of 18 MPH (29 KMH)
and all the doors are closed. If a door is opened and
the vehicle slows to below 18 MPH (29 KMH), thedoor locks will operate again once all doors are
closed and the speed is above 15 MPH (24 KMH).
3.15.4 REMOTE KEYLESS ENTRY (RKE)
The body control module interfaces with the RKE
module via a one-way serial bus interface. The RKE
module is not on the PCI bus. The RKE module
sends a 0-5 volt pulse width signal to the BCM
depending on which button on the transmitter was
pressed. The BCM controls the door lock/unlock
functions and the arming/disarming of the Vehicle
Theft Security System (if equipped) and the activa-
tion of illuminated entry. The BCM will also send
the appropriate messages to the Power Sliding
Doors and Power Liftgate modules. The Intelligent
Power Module (IPM) activates the park lamps,
headlamps, and horn for horn chirp when sent the
appropriate message from the BCM as received
from the RKE transmitter. When a one-button
press is made for unlock, both driver side doors will
unlock and the front and rear turn signal will flash.
When a second press is initiated (within 5 seconds
of the first) both passenger doors will unlock and all
four turn signals will flash.
The RKE module is capable of retaining up to 4
individual access codes (4 transmitters). If the
PRNDL is in any position except park, the BCM will
ground the interface thereby disabling the RKE.
The 2 button transmitter will have 2-CR2016
batteries in series. The 5 button transmitter will
have 1-CR2016 battery. The minimum battery life
should be approximately 4.7 years based on 20
transmissions a day at 84ÉF (25ÉC). Using the
DRBIIItand selecting RKE FOB Test can test the
transmitter.
The RKE module can be programmed via the
DRBIIItor the customer programming method.
The BCM will only allow programming mode to be
entered when the ignition is in the on position, the
PRNDL is in park position, and the VTSS (if
equipped) is in the disarmed mode.
3.16 POWER FOLDING MIRRORS
The power folding mirrors are powered to two
positions: folded and unfolded. The driver may
choose fold or unfold with a switch that is located on
the right side of the steering column. The folding
mirror switch grounds a sense wire that comes from
the Body Control Module when it is placed in the
fold position. The mirrors will move to the position
designated by the switch whether the ignition
switch is the On or Off position and both front doors
are closed. When the Power Folding Mirror switch
is left in the fold position during a vehicle exit the
mirrors will automatically unfold then refold after
both front doors are closed. This is to prevent mirror
contact with either front door when opened. When
24
GENERAL INFORMATION

manual sliding door. When the child lock out switch
is on, the B pillar switches are disabled.
There is only one part number for the power
sliding door module (PSDM). The driver sliding
door harness has an additional ground circuit which
will identify it as the driver side. This eliminates
the need for a left and a right side module.
3.18.2 DIAGNOSTIC FEATURES
The PSDM can be flashed on vehicle via PCI bus
with a DRBIIItdiagnostic tool. The DRBIIItcan
read all inputs, actuate all outputs, read module
information, and read diagnostic trouble codes. As a
reminder, some DTC's can be set during normal
PSD operation.
3.18.3 SYSTEM INHIBITORS
1. Battery voltage too high or too low (above 16V,
below 9.5V)
2. Vehicle in gear
3. Vehicle speed > 0 mph/km/h
4. Child locks enabled inhibit the B pillar switch
operation
5. O/H console lockout will inhibit the B pillar
switches
6. Doors locked will inhibit all interior switches
from opening (Overhead Console, B Pillar). A
locked sliding door can be power closed.
3.19 REAR WINDOW DEFOG/HEATED
MIRROR/FRONT WIPER DE-ICE
The defroster button located on the HVAC control
controls the rear window defogger, heated side view
mirrors and front wiper de-icer grid. In addition the
front wiper de-ice function is turned on when front
defog/defrost mode is selected.
When the defroster button is pushed, the HVAC
control sends a bus message over the PCI bus to the
Front Control Module (FCM) which controls the
Rear Window Defogger relay. The defroster LED
will illuminate when the defroster function is on.
The defroster will function for 10 minutes or can be
cycled off sooner by pressing the defroster button
again. The front wiper de-icer grid receives its 12
volts from the accessory relay through fuse 11 and
the HVAC control module supplies the grid ground.
3.20 VEHICLE THEFT SECURITY SYSTEM
3.20.1 BASE ALARM SYSTEM
The Vehicle Theft Security System (VTSS) is part
of the Body Control Module (BCM). The BCM
monitors the vehicle doors, liftgate, hood, and theignition for unauthorized operation. The alarm ac-
tivates by sounding the horn, flashing the head-
lamps and the VTSS indicator lamp. The VTSS does
not prevent engine operation, this is done with the
Sentry Key Immobilizer Module (SKIM). Passive
arming occurs in one of two ways. Upon normal
vehicle exit by removing the ignition key, opening
the driver door, locking the doors with the power
lock, and closing the driver door, or by removing the
ignition key, opening the driver door, closing the
driver door, and locking the doors with the Remote
Keyless Entry (RKE) transmitter. The VTSS indi-
cator lamp will flash for approximately 15 seconds
during the arming process. If there is no interrup-
tion during the arming process, upon completion
the VTSS indicator lamp will flash at a slower rate.
When the BCM receives an input to trigger the
alarm, the BCM will control the outputs of the
headlamps, horn, and VTSS lamp for approxi-
mately 18 minutes.
Arming (Active and Passive)
Active arming occurs when the RKE transmitter
is used to lock the vehicle doors, whether the doors
are open or closed. The arming process is complete
only after all doors are closed.
Passive arming occurs when the ignition key is
removed, the driver door is opened, and the doors
are locked with the power door lock switch, and the
door is closed.
Disarming (Active and Passive)
Active disarming occurs when the RKE transmit-
ter is used to unlock the vehicle doors. This disarm-
ing will also halt the alarm once it has been acti-
vated.
Passive disarming occurs upon normal vehicle
entry (unlocking driver door with the key). This
disarming will also halt the alarm once it has been
activated.
Tamper Alert
The VTSS tamper alert will sound the horn three
times upon disarming to indicate a tamper condi-
tion has occurred.
Manual Override
The system will not arm if the doors are locked
using the manual lock control or if the locks are
actuated by an inside occupant after the doors are
closed.
Diagnosis
For complaints about the Vehicle Theft Alarm
triggering on its own, use the DRBIIItand read the
Last VTSS Cause status.
26
GENERAL INFORMATION

NOTE: A POWERTRAIN CONTROL MODULE
FROM A VEHICLE EQUIPPED WITH A
VEHICLE THEFT SECURITY SYSTEM
CANNOT BE USED IN A VEHICLE THAT IS
NOT EQUIPPED WITH A VEHICLE THEFT
SECURITY SYSTEM IF THE VTSS INDICATOR
LAMP COMES ON AFTER IGNITION ON AND
STAYS ON, THE PCI BUS COMMUNICATION
WITH THE POWERTRAIN CONTROL
MODULE HAS POSSIBLY BEEN LOST.
3.20.2 THATCHAM ALARM SYSTEM
The Thatcham Alarm Module monitors the vehi-
cle doors, liftgate, hood and the interior of the
vehicle for unauthorized operation. The vehicle
doors, liftgate, and hood use ajar switches as inputs
to the BCM to indicate their current status. The
interior of the vehicle is secured by the use of
Intrusion Sensors. The Intrusion Sensors are used
as inputs to the RKE/Thatcham Alarm Module to
report any motion in the interior of the vehicle. The
alarm activates by sounding the siren, flashing the
hazard lamps, and the VTSS Indicator Lamp.
Arming
Before arming, all doors, liftgate, and the hood
must be completely closed. The system can then be
armed by following a normal exit sequence, of
opening the door and then locking the doors with
the door lock switch and then closing the door. The
system can also be armed by opening the door,
closing the door and then locking the doors with the
RKE transmitter.
Disarming
To disarm the alarm system, the RKE transmit-
ter is used. The RKE transmitter will unlock the
vehicle doors and disarm the alarm system. The
RKE transmitter can also be used to halt the alarm
once it has been activated.
3.21 WIPER SYSTEM
3.21.1 FRONT WIPER
The front wiper/washer system consists of the
following features: lo-hi-speed, mist wipers, inter-
mittent wipers and wipe after wash. The front
wiper system is only active when the ignition switch
is in the RUN/ACC position. The vehicle operator
selects the front wiper function using the front
wiper switch (a resistive multiplexed stalk switch)
which is integral to the Multi-Function Switch. The
front wiper switch is hardwired to the Body Control
Module (BCM). Upon receiving a wiper switch sig-
nal, the BCM sends a PCI Bus message to the Front
Control Module (FCM). The FCM controls the ON/OFF relay, the HIGH/LOW relay and the front and
rear washer pump motors.
The Wiper system utilizes the BCM to control the
on/off and hi/low relays for the low and hi speed
wiper functions, intermittent wiper delay as the
switch position changes, pulse wipe, wipe after
wash mode and wiper motor functions. The BCM
uses the vehicle speed input to double the usual
delay time below 10 MPH (6 KPH).
3.21.2 SPEED SENSITIVE INTERMITTENT
WIPE MODE
There are 5 individual delay time settings with a
minimum delay of 1.7 seconds to a maximum of 18.4
seconds. When the vehicle speed is under 10 MPH
(6 KPM), the delay time is doubled, providing a
delay range of 3.4 seconds to 36.8 seconds.
3.21.3 PULSE WIPE
When the wiper is in the off position and the
driver presses the wash button for more than .062
seconds, but less than .5 seconds, 2 wipe cycles in
low speed mode will be provided.
3.21.4 PARK AFTER IGNITION OFF
Because the wiper relays are powered from the
battery, the BCM can run the wipers to park after
the ignition is turned off.
3.21.5 WIPE AFTER WASH
When the driver presses the wash button for over
.5 seconds and releases it, the wiper will continue to
run for 2 additional wipe cycles.
3.21.6 REAR WIPER
The rear wiper/washer system consists of the
following features: mist wipers, intermittent wipers
and wipe after wash. The rear wiper system is only
active when the ignition switch is in the RUN/ACC
position. The vehicle operator selects the rear wiper
function using one of the three buttons on the dash
mounted rear wiper switch. The rear wiper switch
is hardwired to the Body Control Module (BCM).
Upon receiving a wiper switch signal, the BCM
provides 12 volts to the rear wiper motor. Rear
washer occurs when the BCM receives a rear
washer switch ON input. The BCM sends a PCI Bus
message to the FCM requesting rear washer on.
The FCM activates the rear washer by providing a
ground for the rear washer motor.
3.21.7 SPEED SENSITIVE INTERMITTENT
WIPE MODE
The delay setting of the rear wiper system is
based solely on the vehicle speed. The delay time is
27
GENERAL INFORMATION

When diagnosing a chassis system problem, it is
important to follow approved procedures where
applicable. These procedures can be found in this
General Information Section or in the service man-
ual procedures. Following these procedures is very
important to safety of individuals performing diag-
nostic tests.
4.2.2 VEHICLE PREPARATION FOR
TESTING
Make sure the vehicle being tested has a fully
charged battery. If it does not, false diagnostic codes
or error messages may occur.
4.2.3 SERVICING SUB-ASSEMBLIES
Some components of the chassis system are in-
tended to be serviced as an assembly only. Attempt-
ing to remove or repair certain system sub-
components may result in personal injury and/or
improper system operation. Only those components
with approved repair and installation procedures in
the service manual should be serviced.
4.2.4 DRBIIITSAFETY INFORMATION
WARNING: EXCEEDING THE LIMITS OF THE
DRBIIITMULTIMETER IS DANGEROUS. IT
CAN EXPOSE YOU TO SERIOUS OR
POSSIBLY FATAL INJURY. CAREFULLY
READ AND UNDERSTAND THE CAUTIONS
AND THE SPECIFICATION LIMITS.
²Follow the vehicle manufacturer 's service speci-
fications at all times.
²Do not use the DRBIIItif it has been damaged.
²Do not use the test leads if the insulation is
damaged or if metal is exposed.
²To avoid electrical shock, do not touch the test
leads, tips, or the circuit being tested.
²Choose the proper range and functions for the
measurement. Do not try voltage or current mea-
surement that may exceed the rated capacity.
²Do not exceed the limits shown in the table below:
FUNCTION INPUT LIMIT
Volts 0 - 500 peak volts AC
0 - 500 volts DC
Ohms (resistance)* 0 -1.12 megohms
Frequency Measured
Frequency Generated0-10kHz
Temperature -58 - 1100ÉF
-50 - 600ÉC* Ohms cannot be measured if voltage is present.
Ohms can be measured only in a non-powered
circuit.
²Voltage between any terminal and ground must
not exceed 500v DC or 500v peak AC.
²Use caution when measuring voltage above 25v
DC or 25v AC.
²Use the low current shunt to measure circuits up
to 10A. Use the high current clamp to measure
circuits exceeding 10A.
²When testing for the presence of voltage or cur-
rent, make sure the meter is functioning cor-
rectly. Take a reading of a known voltage or
current before accepting a zero reading.
²When measuring current, connect the meter in
series with the load.
²Disconnect the live test lead before disconnecting
the common test lead.
²When using the meter function, keep the
DRBIIItaway from spark plug or coil wires to
avoid measuring error from outside interference.
4.3 WARNINGS
4.3.1 VEHICLE DAMAGE WARNINGS
Before disconnecting any control module, make
sure the ignition is ªoffº. Failure to do so could
damage the module.
When testing voltage or continuity at any control
module, use the terminal side (not the wire end) of
the connector. Do not probe a wire through the
insulation; this will damage it and eventually cause
it to fail because of corrosion. Be careful when
performing electrical tests so as to prevent acciden-
tal shorting of terminals. Such mistakes can dam-
age fuses or components. Also, a second code could
be set, making diagnosis of the original problem
more difficult.
4.3.2 ROAD TESTING A COMPLAINT
VEHICLE
Some complaints will require a test drive as part
of the repair verification procedure. The purpose of
the test drive is to try to duplicate the diagnostic
code or symptom condition.
29
GENERAL INFORMATION