driver seat adjustment CHRYSLER VOYAGER 2001 Service Manual

the CPA is not properly engaged, a voltage on pin 38
will be interpreted as an unseated connector and a
fault will set.
Flash programming voltage Ð20 volt input on
pin 42. When a DRBIIItis connected and the
proper flash reprogramming sequence is selected,
the 20 volt signal will be applied through pin 42.
3.9 HEATING & A/C
3.9.1 AUTOMATIC TEMPERATURE
CONTROL (ATC)
3.9.1.1 CABIN HEATER
For vehicles equipped with a diesel engine, a
Cabin Heater is used in conjunction with the HVAC
system. The Cabin Heater is designed to supply the
vehicle's occupants with heat prior to the engine
reaching operating temperature. For additional in-
formation on this system, refer to Cabin Heater
under General Information and Diagnostic Proce-
dures in this manual.
3.9.1.2 SYSTEM OPERATION
The Automatic Temperature Control (ATC) sys-
tem provides fully adjustable three zone climate
control; Driver front zone, Passenger Front zone
and Rear zone. The following is a list of ATC
controls and features:
± a POWER button which allows the operator to
turn the system completely off.
± AUTO HIGH/LOW switch allows the operator
to select what rate (fan speed) the system will
provide the selected comfort level.
± DRIVER, REAR and PASSENGER rocker
switches to select desired temperature for each
zone.
± Recirculation button allows cooling air to be
recirculated which maximizes cooling ability.
± A/C select button allows the operator to turn
the A/C compressor off.
± Defroster button allows the operator to turn on
the defroster independently during automatic
control.
± Fan control rotary switch for selecting fan
speed.
± Mode rotary switch for selecting heating/
cooling direction.
± REAR SYSTEM rotary switch for activating
the Rear ATC Switch allowing intermediate
passenger control over rear climate control.
3.9.1.3 BLOWER MOTOR OPERATION
The Automatic Temperature Control (ATC) front
and rear blower control provides continuously vari-
able control of air flow rate to meet occupant
comfort requirements. Pulse width modulation of
the blower motor power allows the front and rear
blower to operate at any speed from off to full speed.
When front or rear blower operation is required, the
ATC sends a PCI Bus message to the Front Control
Module (FCM) requesting blower relay ON. The
FCM provides a ground for the front and rear
blower motor relay coils, activating both relays. The
front and rear blower relays provide 12 volts to
their respective blower motor power modules. Each
module provides a 12 volt blower motor control
signal to the ATC. The ATC provides a pulse width
modulated (duty-cycle) ground signal to this circuit
based on climate requirements. The higher voltage
on the signal circuit (less duty-cycle ground) the
lower the blower speed request. The lower voltage
on the signal circuit (more duty-cycle ground) the
higher the blower speed request.
3.9.1.4 INFRARED SENSORS
The ATC system uses infrared (I/R) sensors to
monitor and control oocupant comfort levels. This
sensing system replaces interior air temperature
and solar sensors which required complex control
programs to maintain occupant comfort levels. The
front I/R sensor is located in the instrument panel
center bezel outlet. The rear I/R sensor is located in
the rear overhead mounted ATC switch.
3.9.1.5 REAR ATC SWITCH
The rear ATC switch is mounted in the headliner.
The switch contains a rotary adjustment for fan
speed, a rotary adjustment for mode selection, a
push button switch for temperature selection and a
digital display of the selected temperature.
3.9.1.6 COOLDOWN TESTING
The ATC provides a feature referred to as a
Cooldown Test. This test is initiated using the
DRBIIItand is designed to check the performance
of the air conditioning system. The ATC will not
perform this test if the ambient air temperature is
below 12ÉC (53ÉF). During the test, the ATC com-
pares the ambient air temperature to the evapora-
tor temperature sensor. To pass the cooldown test,
the evap temperature sensor must drop -6ÉC (20ÉF)
below ambient temperature within 2 minutes of
start of test. At the completion of the cooldown test
the DRBIIItwill display one of the following mes-
sages indicating test outcome:
± Cooldown Test Passed
± Cooldown Test Failed
16
GENERAL INFORMATION

contains a potentiometer to monitor the seat posi-
tion. To monitor the position of the motor, the
MSMM sends out a 5-volt reference on the sensor
supply circuit. The sensor is grounded back to the
module on a common ground circuit. Based on the
position of the sensor, the MSMM monitors the
voltage change through the sensor on a separate
signal circuit.
The MSMM stores the input value of each of the
four seat potentiometers in memory when the sys-
tem requests a set. The driver can initiate a mem-
ory recall, using either the door mounted memory
switch or the RKE transmitter (if the remote linked
to memory feature is enabled via the EVIC). When
initiated, the MSMM adjusts the four seat sensors
(by using the motors) to match the memorized seat
position data.
For safety, the memory seat recall is disabled by
the MSMM when the vehicle is out of park position
or if the speed is not zero. Any obstruction to seat
movement over a 2-second delay will cause the seat
to stop moving in which case a stalled motor would
be detected by the MSMM and the corresponding
seat output would be deactivated. However, if the
object obstructing the seat is removed, the seat will
function normally again.
3.13.2 MEMORY MIRRORS
Each outside mirror contains vertical and hori-
zontal bi-directional drive positioning motors and
position sensors. The MSMM provides a 5-volt
reference on the signal circuit to each position
sensor. The sensors share a common ground circuit.
The MSMM monitors the position of the mirror
motors by measuring the voltage on each signal
circuit. When a memory position is set, the MSMM
monitors and stores the position of the outside
mirrors. The MSMM adjusts the mirrors to the
appropriate positions when a memory recall mes-
sage is received from the RKE or is requested from
the memory set switch.
The power mirror switch during non-memory
operation operates both mirrors independently of
the MSMM.
3.14 OVERHEAD CONSOLE
3.14.1 COMPASS/MINI-TRIP COMPUTER
(CMTC)
The compass/mini-trip computer is located in the
overhead console. It displays to the driver the
direction the vehicle is traveling and the current
outside temperature, as well as the following trav-
eler navigational information: average fuel econ-
omy (AVG ECO), distance to empty (DTE), instan-
taneous fuel economy (ECO), elapsed time (ET),and trip odometer (ODO). The information needed
for the CMTC functions is received over the PCI bus
from other modules.
3.14.2 ELECTRONIC VEHICLE
INFORMATION CENTER (EVIC)
The Electronic Vehicle Information Center
(EVIC) includes all the same functions and is lo-
cated in the same area as the Compass/Mini-Trip
Computer, but it adds a number of warning mes-
sages. Also, the EVIC messages are spelled out on
the screen, for example, DISTANCE TO EMPTY,
where the Mini-Trip Computer displays only shows
DTE.
If the compass/mini-trip computer or EVIC has
been replaced, it may be necessary to reset the
calibration.
3.14.3 SETTING THE COMPASS
The compass/mini-trip computer and EVIC are
self-calibrated and requires no adjustment. The
word CAL will be displayed to indicate that the
compass is in the fast calibrating mode. CAL will
turn off after the vehicle has gone in three complete
circles without stopping, in an area free of magnetic
disturbance.
If the module displays the temperature while the
compass is blank or shows a false reading, the
vehicle must be demagnetized. See the service man-
ual for the proper procedure.
If the compass still goes blank after the vehicle is
demagnetized, the compass/mini-trip/EVIC module
must be replaced.
3.14.4 SETTING THE VARIANCE
Variance is the difference between magnetic
north and geographic north. To determine the vari-
ance for the area you are in, refer to the following
zone map provided. The number shown for your
area is the variance number for your area.
1. Set the compass/mini-trip computer (CMTC) to
compass/temperature mode.
2. Press and hold down the RESET button for 5
seconds.NOTE:If the button is held for 10
23
GENERAL INFORMATION

The outboard rear disc brake shoes (pads) are side-
oriented. The shoes are marked indicating which side
they belong on.
DESCRIPTION - DRUM BRAKES (REAR)
This vehicle's rear wheel drum brakes are a two-
shoe, internal-expanding type with an automatic
adjuster screw. The automatic adjuster screw is
located directly below the wheel cylinder that is
mounted near the top of the brake assembly (Fig.
10). These and two brake shoes (and attaching parts)
are mounted to a support plate at each rear wheel. A
brake drum covers each brake assembly.
OPERATION - DISC BRAKES (FRONT)
When the brakes are applied, fluid pressure is sent
to each brake caliper. The pressure at the caliper is
exerted equally against the caliper piston. The pres-
sure applied to the piston is transmitted directly to
the inboard brake shoe. This forces the shoe lining
against the inner surface of the brake rotor. At the
same time, fluid pressure within the caliper piston
bore forces the caliper to slide inward on its guide
pins. This action brings the outboard shoe lining into
contact with the outer surface of the brake rotor.
This pressure on both sides of the brake rotor causes
friction, bringing the vehicle to a stop.
When the brake pedal is released, so is the fluid
pressure. The piston seal inside the caliper is
designed to pull the piston back into the bore of the
caliper when the brake pedal is released (Fig. 11).
This action helps maintain the proper brake shoe-to-
rotor clearance.As disc brake shoe linings wear, master cylinder
reservoir brake fluid level will drop. Adjust as neces-
sary. Fluid level should always be checked after
replacing shoes.
OPERATION - DISC BRAKES (REAR)
The rear disc brakes operate similarly to front disc
brakes, however, there are some features that require
different service procedures.
DIAGNOSIS AND TESTING - DRUM BRAKE
AUTOMATIC ADJUSTER
The rear drum brakes on this vehicle automatically
adjust when required during the normal operation of
the vehicle every time the brakes are applied. Use
the following procedure to test the operation of the
automatic adjuster.
Place the vehicle on a hoist with a helper in the
driver's seat to apply the brakes. Remove the access
plug from the adjustment hole in each brake support
plate to provide visual access of the brake adjuster
star wheel.
To eliminate the condition where maximum adjust-
ment of the rear brake shoes does not allow the auto-
matic adjuster to operate when tested, back the star
wheel off approximately 30 notches. It will be neces-
sary to hold the adjuster lever away from the star
wheel to permit this adjustment.
Have the helper apply the brakes. Upon applica-
tion of the brake pedal, the adjuster lever should
move down, turning the adjuster star wheel. Thus, a
definite rotation of the adjuster star wheel can be
Fig. 10 Drum Brake Assembly (Right Shown)
1 - WHEEL CYLINDER
2 - BRAKE SHOE UPPER RETURN SPRING
3 - AUTOMATIC ADJUSTER LEVER
4 - TENSION CLIP
5 - AUTOMATIC ADJUSTER ASSEMBLY
Fig. 11 Caliper Piston Seal Function For Automatic
Adjustment
1 - PISTON
2 - CYLINDER BORE
3 - PISTON SEAL BRAKE PRESSURE OFF
4 - CALIPER HOUSING
5 - DUST BOOT
6 - PISTON SEAL BRAKE PRESSURE ON
5 - 12 BRAKES - BASERS
HYDRAULIC/MECHANICAL (Continued)

POWER SEAT TRACK
DESCRIPTION
The eight-way power seat options include a single
electrically operated power seat track unit located
under each front bucket seat (Fig. 9). The power seat
track unit replaces the standard equipment manual
seat tracks. The lower half of the power seat track is
secured at the front with two bolts to the floor panel
seat cross member, and at the rear with two bolts to
the floor panel. Four nuts secure the bottom of the
seat cushion frame to four studs on the upper half of
the power seat track unit.
The power seat track unit cannot be repaired, and
is serviced only as a complete unit. If any component
in this unit is faulty or damaged, the entire power
seat track unit must be replaced. Refer toBucket
Seat Track Adjusterin the Body section of the ser-
vice manual for the procedure.
OPERATION
The power seat track unit includes three reversible
electric motors that are secured to the upper half of
the track unit. Each motor moves the seat adjuster
through a combination of worm-drive gearboxes and
screw-type drive units. Each of the three driver side
power seat track motors used on models equipped
with the optional memory system also has a position
potentiometer integral to the motor assembly, which
electronically monitors the motor position.
The front and rear of the seat are operated by two
separate vertical adjustment motors. These motors
can be operated independently of each other, tiltingthe entire seat assembly forward or rearward; or,
they can be operated in unison by selecting the
proper power seat switch functions, which will raise
or lower the entire seat assembly. The third motor is
the horizontal adjustment motor, which moves the
seat track in the forward and rearward directions.
DIAGNOSIS AND TESTING - POWER SEAT
TRACK
Following are tests that will help to diagnose the
hard wired components and circuits of the power seat
system. However, if the vehicle is also equipped with
the optional memory system, these tests may not
prove conclusive in the diagnosis of the driver side
power seat. In order to obtain conclusive testing of
the driver side power seat with the memory system
option, the Programmable Communications Interface
(PCI) data bus network and all of the electronic mod-
ules that provide inputs to, or receive outputs from
the memory system components must be checked.
The most reliable, efficient, and accurate means to
diagnose the driver side power seat with the memory
system option requires the use of a DRBtscan tool
and the proper Diagnostic Procedures manual. The
DRBtscan tool can provide confirmation that the
PCI data bus is functional, that all of the electronic
modules are sending and receiving the proper mes-
sages on the PCI data bus, and that the memory sys-
tem is receiving the proper hard wired inputs and
relaying the proper hard wired outputs to perform its
driver side power seat functions.
WARNING: SOME VEHICLES ARE EQUIPPED WITH
SEATBACK MOUNTED AIRBAGS. BEFORE
ATTEMPTING TO DIAGNOSE OR SERVICE ANY
SEAT OR POWER SEAT SYSTEM COMPONENT
YOU MUST FIRST DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE CABLE. THEN WAIT TWO MIN-
UTES FOR THE SYSTEM CAPACITOR TO DIS-
CHARGE BEFORE FURTHER SYSTEM SERVICE.
THIS IS THE ONLY SURE WAY TO DISABLE THE
AIRBAG SYSTEM. FAILURE TO DO SO COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
Actuate the power seat switch to move all three
power seat track adjusters in each direction. The
power seat track adjusters should move in each of
the selected directions. If a power seat track adjuster
fails to operate in only one direction, move the
adjuster a short distance in the opposite direction
and test again to be certain that the adjuster is not
at its travel limit. If the power seat track adjuster
still fails to operate in only one direction, refer to
Power Seat Switchin the Diagnosis and Testing
section of this group. If the power seat track adjuster
Fig. 9 Power Seat Track - Typical
1 - DRIVE UNITS
2 - LOWER SEAT TRACKS
3 - POWER SEAT MOTORS
4 - SEAT CUSHION FRAME
8N - 58 POWER SEATSRS

(10) Install bearing retainer axle seal using Tool
L-4520 (inverted), and driver handle C-4171 (Fig.
160).
(11) Install adapter plate axle seal using Tool
L-4520 (inverted), and driver handle C-4171.
(12) Check differential turning torque. (Refer to 21
- TRANSMISSION/TRANSAXLE/AUTOMATIC -
31TH/BEARINGS - ADJUSTMENTS)
(13) Apply an 1/8º bead of Moparž Silicone Rubber
Adhesive Sealant to the differential cover (Fig. 161).(14) Install differential cover-to-transaxle case
bolts and torque to 19 N´m (165 in. lbs.) torque (Fig.
162).
(15) Install transfer shaft and related components.
ADJUSTMENT - DIFFERENTIAL BEARING
NOTE: Transfer shaft MUST be removed from trans-
axle to obtain an accurate differential turning torque
measurement.
Differential turning torque should be measured
and adjusted during any transaxle or differential
teardown/assembly, or if any of the following parts
are replaced:
²Transaxle case
²Differential carrier
²Differential bearing retainer
²Extension housing
²Differential bearing cups and cones
(1) Position the transaxle assembly vertically on
the support stand, differential bearing retainer side
up.
(2) Install Tool L-4436A into the differential and
onto the pinion mate shaft (Fig. 163).
(3) Rotate the differential at least one full revolu-
tion to ensure the tapered roller bearings are fully
seated.
(4) Using Tool L-4436A and an inch-pound torque
wrench, check the turning torque of the differential
(Fig. 164).Turning torque should be within 5±18
in. lbs.
Fig. 160 Install Bearing Retainer Axle Seal
1 - SPECIAL TOOL L-4520
2 - SPECIAL TOOL C-4171
Fig. 161 Install Differential Cover
1 - GOVERNOR PRESSURE PLUG
2 - DIFFERENTIAL COVER
3 - 1/8 INCH BEAD OF R T V SEALANT
4 - DIFFERENTIAL ASSEMBLY
Fig. 162 Differential Cover Bolts
1 - DIFFERENTIAL COVER
2 - DIFFERENTIAL COVER BOLT
21 - 96 AUTOMATIC - 31THRS
FINAL DRIVE (Continued)

DIFFERENTIAL BEARING SHIM CHART
PART NUMBER SHIM THICKNESS
MM INCH
4659257 .980 0.0386
4659258 1.02 0.0402
4659259 1.06 0.0418
4659260 1.10 0.0434
4659261 1.14 0.0449
4659262 1.18 0.0465
4659263 1.22 0.0481
4659264 1.26 0.0497
4659265 1.30 0.0512
4659266 1.34 0.0528
4659267 1.38 0.0544
4659268 1.42 0.0560
4659269 1.46 0.0575
4659270 1.50 0.0591
4659271 1.54 0.0607
4659272 1.58 0.0623
4659273 1.62 0.0638
4659274 1.66 0.0654
4659275 1.70 0.0670
4659283 2.02 0.0796
4659284 2.06 0.0812
PRELOAD ADJUSTMENT W/O SHIM
(1) Remove the bearing cup from the differential
bearing retainer using Miller special Tool 6062A.
(2) Remove existing shim from under bearing cup.
(3) Reinstall the bearing cup into the retainer
using Miller Special Tool 6061, and C-4171.
NOTE: Oil baffle is not required when making the
shim calculation.
(4) Install the bearing retainer into the case.
Torque bolts to 28 N´m (250 in. lbs.).
(5) Position the transaxle assembly vertically on
the support stand and install Miller Special Tool
L-4436-A into the bearing retainer.
(6)
Rotate the differential at least one full revolution
to ensure the tapered roller bearings are fully seated.
(7)Attach a dial indicator to the case and zero the
dial. Place the tip on the end of Special Tool L-4436-A.
(8) Place a large screwdriver to each side of the
ring gear and lift. Check the dial indicator for the
amount of end play.
CAUTION: Do not damage the transaxle case and/or
differential retainer sealing surface.(9) Using the end play measurement that was
determined, add 0.18mm (0.007 inch). This should
give you between 5-18 inch pounds of bearing pre-
load. Refer to the Differential Bearing Shim Chart to
determine which shim to use.
(10) Remove the differential bearing retainer.
Remove the bearing cup.
(11) Install the oil baffle. Install the proper shim
combination under the bearing cup.
(12) Install the differential bearing retainer. Seal
the retainer to the housing with Moparž Silicone
Rubber Adhesive Sealant. Torque bolts to 28 N´m
(250 in. lbs.).
(13) Using Miller Special Tool L-4436-A and an
inch-pound torque wrench, check the turning torque
of the differential (Fig. 213). The turning torque
should be between 5-18 inch-pounds.
NOTE: If turning torque is too high install a 0.05mm
(0.002 inch) thicker shim. If the turning torque is too
low, install a 0.05mm (0.002 inch) thinner shim.
Repeat until 5-18 inch-pounds of turning torque is
obtained.
RSAUTOMATIC - 41TE21 - 245
FINAL DRIVE (Continued)

(25) Measure OD clutch pack clearance. Set up
dial indicator on top of the OD/Reverse reaction plate
as shown in (Fig. 283).
(26) Zero dial indicator and apply 30 psi (206 kPa)
air pressure to the overdrive clutch hose on Tool
8391. Measure and record OD clutch pack measure-
ment in four (4) places, 90É apart.
(27) Take average of four measurements and com-
pare with OD clutch pack clearance specification.
The overdrive (OD) clutch pack clearance is
1.07-3.25 mm (0.042-0.128 in.).
If not within specifications, the clutch is not
assembled properly. There is no adjustment for the
OD clutch clearance.
(28) Install reverse clutch pack (two frictions/one
steel) (Fig. 284).
(29) Install reverse clutch reaction plate with the
flat side down towards reverse clutch (Fig. 285).
(30) Tap reaction plate down to allow installation
of the reverse clutch snap ring. Install reverse clutch
snap ring (Fig. 286).(31) Pry up reverse reaction plate to seat against
snap ring (Fig. 287).
(32) Set up a dial indicator on the reverse clutch
pack as shown in (Fig. 288).
(33) Using moderate pressure, press down and
hold (near indicator) reverse clutch disc with screw-
driver or suitable tool and zero dial indicator (Fig.
289). When releasing pressure, indicator should
advance 0.005-0.010. as clutch pack relaxes.
Fig. 283 Measure OD Clutch Pack Clearance
1 - DIAL INDICATOR
2 - OD/REVERSE REACTION PLATE
Fig. 284 Install Reverse Clutch Pack
1 - REVERSE CLUTCH PLATE
2 - REVERSE CLUTCH DISCS
Fig. 285 Install Reaction Plate
1 - REVERSE CLUTCH REACTION PLATE (FLAT SIDE DOWN)
21 - 266 AUTOMATIC - 41TERS
INPUT CLUTCH ASSEMBLY (Continued)

(2) Remove the armrest. (Refer to 23 - BODY/
SEATS/ARMREST - REMOVAL).
(3) Remove the seatback recliner lever.
(4) Remove the lumbar adjustment lever.
(5) Remove both seat cushion side covers. (Refer to
23 - BODY/SEATS/FRONT SEAT CUSHION SIDE
COVER - REMOVAL).
(6) Remove nut attaching the recliner to the seat-
back frame (Fig. 15).
(7) Remove both pivot bolts and remove seatback
from recliner.
INSTALLATION
(1) Place seat back into position.
(2) Install both pivot bolts attaching seat back
frame to seat track. Tighten bolts to 54 N´m (40 ft.
lbs.) torque.
(3) Install nut attaching the recliner to the seat
back frame. Tighten nut to 12 N´m (105 in. lbs.)
torque.
(4) Install both seat cushion side covers. (Refer to
23 - BODY/SEATS/FRONT SEAT CUSHION SIDE
COVER - INSTALLATION).
(5) Install the lumbar adjustment lever.
(6) Install the seat back recliner lever.
(7) Install the armrest. (Refer to 23 - BODY/
SEATS/ARMREST - INSTALLATION).(8) Install headrest sleeves. (Refer to 23 - BODY/
SEATS/HEADREST SLEEVE - INSTALLATION).
FRONT SEATBACK ASSIST
STRAP
REMOVAL
(1) Using a small screw driver, pry screw plugs
from ends of assist strap (Fig. 16).
(2) Remove screws attaching assist strap to seat-
back.
(3) Remove assist strap from vehicle.
INSTALLATION
(1) Place assist strap in position on vehicle.
(2) Install screws attaching assist strap to seat
back. Tighten screws to 2.5 N´m (22 in. lbs.).
(3) Insert screw plugs into ends of assist strap
(Fig. 16).
FRONT SEATBACK PANEL
REMOVAL
(1) Remove the screws (Fig. 17).
(2) Tip the top of the panel away from the seat
back and lift off the hooks at the bottom to remove.
INSTALLATION
(1) Place seat back cover onto the seat and engage
the bottom hooks.
Fig. 15 FRONT SEATBACK
Fig. 16 FRONT SEATBACK ASSIST STRAP
1 - ASSIST STRAP
2 - SCREW PLUG
3 - SEAT BACK
23 - 228 SEATSRS
FRONT SEATBACK (Continued)

²an air conditioning button that allows the com-
pressor to be turned on/off. The Snowflake button
contains an LED that illuminates to shown when the
function is in operation.
²rotary knobs for front and rear fan speed selec-
tion.
²a rotary knob for mode control.
REAR CONTROL PANEL
A rear control panel centrally mounted on the
headliner has a rotary adjustment for temperature
and fan speed control of the rear unit by intermedi-
ate seat passengers when the front control rear knob
is set to the rear position.
DESCRIPTION - THREE ZONE Automatic
Temperature Control
The Three-Zone Automatic Temperature Control
(ATC) allows occupants to select a comfort tempera-
ture, which is the perceived temperature level not
the actual passenger compartment air temperature.
The Three Zone Automatic Temperature Control
system includes a dust and odor air filter. The filter
element is the same size as the air conditioning evap-
orator to ensure ample capacity. A door at the base of
the heater and air conditioning housing below the
glove box provides easy access to the filter element.
The ATC computer utilizes integrated circuitry and
information carried on the Programmable Communi-
cations Interface (PCI) data bus network to monitor
many sensors and switch inputs throughout the vehi-
cle. In response to those inputs, the internal circuitry
and programming of the ATC computer allow it to
control electronic functions and features of the ATC
system. The inputs to the ATC computer are:
²Vehicle Speed/Engine RPM± The ATC com-
puter monitors engine RPM, vehicle speed and Man-
ifold Absolute Pressure information from the PCM.
²Coolant Temperature± ATC computer moni-
tors Coolant temperature received from the PCM and
converts it to degrees Fahrenheit.
²Ambient Temperature± ATC computer moni-
tors Ambient temperature from the Compass Mini
Trip Computer (CMTC) and converts it to degrees
Fahrenheit.
²Engine Miscellaneous Sensor Status±ATC
computer monitors A/C disable information from the
PCM.
²Refrigerant Pressure± ATC computer moni-
tors Barometric Pressure, Intake Air Temperature,
High Side Pressure and Methanol Content as broad-
cast by the PCM.
²Door Ajar Status± The ATC computer moni-
tors Driver Front Door, Passenger Front Door, Left
Rear Door, Right Rear Door and Liftgate ajar infor-
mation, as identified by the Body Control Module(BCM), to determine if all in-car temperatures should
be maintained.
²Dimming± The ATC computer monitors dim-
ming status from the BCM to determine the required
level of brightness and will dim accordingly.
²Vehicle Odometer± The ATC computer moni-
tors the vehicle odometer information from the BCM
to prevent flashing the VF tube icons if the manual
motor calibration or manual cooldown tests have
failed. Flashing of the display icons will cease when
the vehicle odometer is greater than 3 miles.
²English Metric± The ATC computer monitors
the English/Metric information broadcast by the
CMTC. The set temp displays for both the front and
rear control heads will be set accordingly.
²Vehicle Identification Number± The ATC
computer monitors the last eight characters of the
VIN broadcast by the PCM and compares it to the
information stored in EEPROM. If it is different, the
new number will be stored over the old one and a
motor calibration shall be initiated.
²A/C System Information± The ATC computer
will send a message for Evaporator Temperature too
Low, Fan Blower Relay status, Evaporator Sensor
Failure, Rear Window Defogger Relay and A/C Select.
FRONT CONTROL PANEL
The front control panel and integral computer is
mounted in the instrument panel.
The instrument panel mounted control and inte-
gral computer contains:
²A power button which allows the system to be
completely turned off. The display is blank when the
system is off.
²Three rocker switches that select comfort tem-
peratures from 15É to 30É C (59É to 85É F), which are
shown in the vacuum-fluorescent digital control dis-
play. If the set temp is 59 and the down button is
pressed, the set temp value will become 55 but the
display will show LO. If the set temp is 85 and the
up button is pressed, the set temp value will become
90 but the display will show HIGH. Temperatures
can be displayed in either metric or fahrenheit,
which is controlled from the overhead console.
²A rocker switch that selects a cool-down rate.
LO-AUTO or HI-AUTO are displayed when the sys-
tem is in automatic operation.
²A defroster button which turns on the defroster
independently during full automatic control. A
defroster symbol illuminates in the display when the
button is pressed.
²Air recirculation button. A Recirculation symbol
appears in the display when the button is pressed, or
when the system exceeds 80 percent circulated air
under automatic control due to high air conditioning
demand.
24 - 2 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)

²Rear window defogger on/off switch. A graphic
symbol shows when the defroster is on.
²An air conditioning button that allows the com-
pressor to be turned off. A Snowflake symbol is illu-
minated when air conditioning is on, whether under
manual or automatic control.
²Rotary knob for front fan speed selection can
override the automatic controls. LEDs surrounding
the knob show the current setting.
²Rotary knob for control of the Rear system.
²A rotary knob for mode control can override the
automatic controls. LEDs surrounding the knob show
the current setting.
²Computer logic remembers the settings of the
controls when the ignition is turned off and retains
those settings after a restart. If the system is off
when the ignition is turned of, it will be off when the
engine is restarted, etc.
²Computer logic provides variable air recircula-
tion under high temperature and humidity condi-
tions. Because recirculation is generally accompanied
by increased fan noise, the proportion of recirculated
to outside air gradually approaches full recirculation
over a broad temperature range.
²A graphic symbol of the windshield that illumi-
nates when the windshield wiper deicer is active.
REAR CONTROL PANEL
A rear control panel centrally mounted on the
headliner includes a vacuum-flourescent digital dis-
play, a rocker control for temperature and rotary con-
trols for adjustment of mode and fan speed control of
the rear unit by intermediate seat passengers.
OPERATION - DUAL ZONE
²The mode control knob enables continously vari-
able proportioning of air flow between modes but has
detents adjacent to each icon.
²The blower control provides five separate speeds.
²When the fan is off, the HVAC computer closes
the recirculation door to prevent outside air from
entering the passenger compartment.
²Interior air may be recirculated to speed up
heating or cooling in all modes exccept defrost and
mix by pressing the Recirculate button on the control
panel.
²To reduce humidity for rapid defogging the A/C
compressor runs automatically in modes from ªmix'
to full defrost when outside temperautres are above
freezing.
²Air conditioning is available in any mode by
pressing the snowflake, A/C on/off, button.
OPERATION - MANUAL THREE ZONE
FRONT CONTROL PANEL
²Primary control of the rear compartment unit is
on the instrument panel. This control allows the
driver to set the rear compartment fan speed, to turn
the rear unit off, or to give control to the intermedi-
ate seat occupants by switching to the REAR posi-
tion. When the rear unit is controlled from the
instrument panel, rear air temperature is based on
the driver-side temperature control position, and the
mode (floor or overhead air) is based on the front
control's mode position.
²The mode control knob enables continously vari-
able proportioning of air flow between modes but has
detents adjacent to each icon.
²The blower control provides five separate speeds
and Off. When the fan is off, the HVAC computer
closes the recirculation door to prevent outside air
from entering the passenger compartment.
²Interior air may be recirculated to speed up
heating or cooling in all modes exccept defrost and
mix by pressing the Recirculate button on the control
panel.
²To reduce humidity for rapid defogging the A/C
compressor runs automatically in modes from ªmix'
to full defrost when outside temperautres are above
freezing.
²Air conditioning is available in any mode by
pressing the snowflake, A/C on/off, button.
REAR CONTROL PANEL
With the rear control active, temperature selection
dictates indirectly the mode (floor or overhead air) of
the rear unit: a low temperature setting directs flow
to the overhead outlets and a high temperature set-
ting to the floor.
OPERATION - THREE ZONE ATC
Comfort temperature or perceived temperature is
affected by air flow, sun impinging on exposed skin,
etc. The air temperature may be higher or lower than
the comfort temperature. Three infrared sensors, two
in the instrument panel center stack, and one in the
overhead-mounted rear control panel, independently
measure the temperature of the driver, front passen-
ger, and rear compartment occupants to determine
their comfort level relative to the selected comfort
temperature. The HVAC computer in the control
module adjusts the air flow rate and temperature to
maintain the customer-perceived comfort tempera-
ture. The air temperature in the passenger compart-
ment at any time may be slightly higher or lower
than the comfort temperature. For instance, on
sunny summer days the air flow will probably be
cooler than the comfort temperature; on cold or
RSHEATING & AIR CONDITIONING24-3
HEATING & AIR CONDITIONING (Continued)