2001 DODGE TOWN AND COUNTRY seat memory

POWER SEATS
TABLE OF CONTENTS
page page
POWER SEATS
DESCRIPTION...........................49
OPERATION.............................50
DIAGNOSIS AND TESTING.................51
POWER SEAT SYSTEM..................51
MEMORY SYSTEM......................51
DRIVER SEAT SWITCH
DESCRIPTION...........................52
OPERATION.............................52
DIAGNOSIS AND TESTING.................53
DRIVER SEAT SWITCH..................53
REMOVAL..............................53
INSTALLATION...........................54
MEMORY SET SWITCH
DESCRIPTION...........................54
OPERATION.............................54
DIAGNOSIS AND TESTING.................54
MEMORY SWITCH......................54
REMOVAL..............................54
INSTALLATION...........................54PASSENGER SEAT SWITCH
DESCRIPTION...........................55
OPERATION.............................55
DIAGNOSIS AND TESTING.................55
PASSENGER SEAT SWITCH..............55
REMOVAL..............................56
INSTALLATION...........................56
RECLINER MOTOR
DESCRIPTION...........................56
OPERATION.............................56
DIAGNOSIS AND TESTING.................57
POWER SEAT RECLINER................57
POWER SEAT TRACK
DESCRIPTION...........................58
OPERATION.............................58
DIAGNOSIS AND TESTING.................58
POWER SEAT TRACK...................58
REMOVAL..............................59
INSTALLATION...........................59
POWER SEATS
DESCRIPTION - POWER SEAT SYSTEM
The power seat system option allows the driver
and front seat passenger to electrically adjust their
seating positions for optimum control and comfort
using the power seat switches located on the out-
board seat cushion side shield of each front seat. The
power seat system receives battery current through a
40 amp fuse in the Intelligent Power Module and a
30 amp circuit breaker under the seat so that the
power seats remain operational, regardless of the
ignition switch position.
WARNING: SOME VEHICLES ARE EQUIPPED WITH
SEATBACK MOUNTED AIRBAGS (Fig. 1). 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.
Fig. 1 SIDE AIRBAG EQUIPPED SEAT
1 - Airbag Label
RSPOWER SEATS8N-49
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A eight-way power seat is standard on highline
models and optional on others. This option includes a
six-way adjustable seat cushion track and a two-way
power seat back.
The eight-way power seat is also available with the
heated seat and memory seat system that automati-
cally positions the power seat for two different driv-
ers. Refer toHeated Seat Systemfor more
information on the heated seat option. Refer toMem-
ory Systemin the Memory System section of this
group for more information on the memory system.
The power seat system includes the following com-
ponents:
²Power seat recliner
²Power seat switch
²Power seat track.
The power seat system with memory and heated
seat options includes the following components:
²Power seat recliner
²Power seat switch
²Power seat track.
²Memory Heated Seat Module (MHSM)
²Memory set switch
²Heated seat switch
²Electronic Vehicle Information Center (EVIC)
²Programmable Communications Interface (PCI)
data bus network
Refer to Wiring Diagrams for complete circuit dia-
grams. Following are general descriptions and opera-
tions for the major components in the power seat
system and memory seat system.
DESCRIPTION - MEMORY SEAT SYSTEM
An electronic memory and heated seat system is
available on some models. The memory system is
able to store and recall the driver side power seat
positions (including the power recliner position), and
both outside power mirror positions for two drivers.
For vehicles with a radio and heated / memory seat
system connected to the Programmable Communica-
tions Interface (PCI) data bus network, the memory
system is also able to store and recall radio station
presets for two drivers. The memory system also will
store and recall the last station listened to for each
driver, even if it is not one of the preset stations.
The memory system will automatically return to
all of these settings when the corresponding num-
bered and button of the memory switch on the driver
side seat side shield is depressed, or when the doors
are unlocked using the Remote Keyless Entry (RKE)
transmitter. A customer programmable feature of the
memory system allows the RKE recall of memory fea-
tures to be disabled in cases where there are more
than two drivers of the vehicle.
A Memory Heated Seat Module (MHSM) is used on
some models to control and integrate the many elec-tronic functions and features included in the memory
/ heated seat system.
The memory system includes the following compo-
nents:
²Heated seat switch
²Memory heated seat module (MHSM)
²Memory switch
²Position potentiometers on both outside power
mirrors
²Position potentiometers on the driver side power
seat track and power seat recliner motors.
²Radio receiver (if PCI data bus capable).
Certain functions and features of the memory system
rely upon resources shared with other electronic mod-
ules in the vehicle over the Programmable Communica-
tions Interface (PCI) J1850 data bus network. The PCI
data bus network allows the sharing of sensor informa-
tion. This helps to reduce wire harness complexity,
internal controller hardware, and component sensor cur-
rent loads. At the same time, this system provides
increased reliability, enhanced diagnostics, and allows
the addition of many new feature capabilities. For diag-
nosis of these electronic modules or of the PCI data bus
network, the use of a DRBtscan tool and the proper
Diagnostic Procedures manual are recommended.
The other electronic modules that may affect mem-
ory system operation are as follows:
²Body Control Module (BCM)- Refer toBody
Control Modulein Electronic Control Modules for
more information.
²
Electronic Vehicle Information Center (EVIC)
- Refer toElectronic Vehicle Information Center
in Overhead Console Systems for more information.
²Powertrain Control Module (PCM)- Refer to
Powertrain Control Modulein Electronic Control
Modules for more information.
²Radio Receiver- Refer toRadio Receiverin
Audio Systems for more information.
Refer toHeated Seat Systemfor more informa-
tion on the heated seat system. Refer toRemote
Keyless Entry Systemin Power Lock Systems for
more information on the RKE system. Refer to
Power Mirrorin Power Mirrors for more informa-
tion on the mirror position potentiometers. Refer to
Power Seat TrackandPower Seat Reclinerin
the Power Seat System section of this group for more
information on the driver side power seat position
potentiometers.
Refer toPower Seatin the Contents of Wiring
Diagrams for complete circuit diagrams. Following
are general descriptions of the remaining major com-
ponents in the factory-installed memory system.
OPERATION - POWER SEAT SYSTEM
The power seat system allows the driver and/or
front passenger seating positions to be adjusted elec-
8N - 50 POWER SEATSRS
POWER SEATS (Continued)
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trically and independently using the separate power
seat switches found on the outboard seat cushion
side shield of each front seat. See the owner's manual
in the vehicle glove box for more information on the
features, use and operation of the power seat system.
OPERATION - MEMORY SYSTEM
The Memory Seat/Mirror Module (MSMM) will
drive a maximum of 2 motors at a time in a given
direction. If conflicting directions are requested, the
priority for response will be as follows:
²Seat Track Rearward
²Seat Front Down
²Seat Rear Down
²Recliner Rearward
²Seat Track Forward
²Seat Front Up
²Seat Rear Up
²Recliner Forward
The inputs from these switches to the MSMM is a
current limited battery source fed by the MSMM.
This protects the MSMM printed circuit board traces
from acting as fuses. All of these switch contact
inputs to the MSMM are normally closed to ground,
except when actuated.
Soft stops are incorporated to prevent the motor
from being driven into a stall. Should the seat have
restricted travel, refer to Resetting Soft Stops in this
section.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the memory system. For diagnosis of the MSM, the
PCI data bus, or the other electronic modules on the
PCI data bus that provide inputs and outputs for the
memory system, the use of a DRBtscan tool and the
proper Diagnostic Procedures manual are recom-
mended.
ELECTRONIC VEHICLE INFORMATION CENTER
The Electronic Vehicle Information Center (EVIC)
serves as the user interface for the memory system.
It displays memory system status messages and pro-
vides the user with the means for enabling and dis-
abling the many customer programmable features
available on the vehicle, including those for the mem-
ory system.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the EVIC. Refer toElectronic Vehicle Informa-
tion Centerin Overhead Console Systems for more
information on the EVIC.
DIAGNOSIS AND TESTING - POWER SEAT
SYSTEM
Following are tests that will help to diagnose the
hard wired components and circuits of the power seatsystem. 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 (Fig. 1). 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.
Before any testing of the power seat system is
attempted, the battery should be fully-charged and
all of the power seat system wire harness connections
and pins cleaned and tightened to ensure proper cir-
cuit continuity and ground paths. For complete cir-
cuit diagrams, refer toPower Seatin Wiring
Diagrams.
With the dome lamp on, apply the power seat
switch in the direction of the failure. If the dome
lamp dims, the seat may be jamming. Check under
and behind the seat for binding or obstructions. If
the dome lamp does not dim, proceed with testing of
the individual components and circuits.
DIAGNOSIS AND TESTING - MEMORY SYSTEM
CHECK AND RESET SOFT STOPS
To check and reset the power memory seat soft
stops, use the power seat control switches to move
the seat in one direction to the end of travel, allow a
couple of seconds before re-energizing the seat in the
same direction until it stops and for three additional
seconds after it stops. (The amount the seat moved
RSPOWER SEATS8N-51
POWER SEATS (Continued)
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upon the second energizing is the amount the soft
stops have been reprogrammed.
Repeat this procedure for each direction of seat
movement (One at a time).
NOTE: Checking and resetting of the power mem-
ory seat soft stops will not affect the customer's
programmed positions.
DIAGNOSIS AND TESTING MEMORY SYSTEM
In order to obtain conclusive testing of the memory
system, 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 memory system requires the use of a
DRB IIItscan tool and the proper Diagnostic Proce-
dures manual. The DRB IIItscan tool can provide
confirmation that the PCI data bus is functional, that
all of the electronic modules are sending and receiv-
ing the proper messages on the PCI data bus, and
that the memory system is receiving the proper hard
wired inputs and relaying the proper hard wired out-
puts to perform its functions.
Following are diagnostic routines that are built
into the module which can be performed without the
use of a diagnostic scan tool. Refer to Wiring Dia-
grams for complete circuit schematic or connector
pin-out information.
DIAGNOSTIC MODE 1
Diagnostic Mode 1 clears soft limits and sets mem-
ory selector switches (1 and 2) to predetermined val-
ues.
ACTIVATION-Press and hold the S and 1 buttons
for 5 seconds to enter diagnostic mode 1. This mode
is exited at the completion of the mode 1 tasks or
upon grounding the DATA G87 circuit input to the
module.
Mode 1 will:
²Clear all soft limits to their default hard limit
values
²Load memory 1 with default settings corre-
sponding to horizontal rearward, front down, rear
down, and recliner rearward positions
²Load memory 2 with default settings corre-
sponding to horizontal forward, front up, rear up,
and recliner forward positions
DIAGNOSTIC MODE 2
Diagnostic mode 2 provides a way to determine if
the seat/mirror motors and position sensors are con-
nected properly.
ACTIVATION-Press and hold the S and 2 buttons
for 5 seconds to enter diagnostic mode 2. This modeis exited after 5 seconds of switch inactivity or upon
grounding the DATA G87 circuit input by moving the
transmission out of the PARK position.
Mode 2 will:
²Place the seat and mirror motors at their mid-
point
²When a single axis of seat or mirror motion is
requested by pressing a switch, the corresponding
motor is energized. This tests switch input and motor
output
DRIVER SEAT SWITCH
DESCRIPTION
Vehicles equipped with power seats utilize a eight-
way power seat switch. This eight-way power seat
switch features two knobs ganged together on the
outboard seat cushion side shield (Fig. 2).
The switch is secured to the back of the seat cush-
ion side shield with two screws. However, the control
knobs for the seat switch unit must be removed
before the seat switch can be removed from the side
shield.
The power seat switch cannot be repaired. If one
switch is damaged or faulty, the entire power seat
switch unit must be replaced.
OPERATION
The power seat tracks can be adjusted in eight dif-
ferent ways using the power seat switches. See the
owner's manual in the vehicle glove box for more
information on the power seat switch functions and
the seat adjusting procedures.
When a power seat switch control knob or knobs
are actuated, a battery feed and a ground path are
applied through the switch contacts to the power seat
track or recliner adjuster motor. The selected
adjuster motor operates to move the seat track or
recliner through its drive unit in the selected direc-
tion until the switch is released, or until the travel
Fig. 2 Power Seat Switch - Typical
8N - 52 POWER SEATSRS
POWER SEATS (Continued)
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(7) Remove the power seat switch from the out-
board seat cushion side shield.
INSTALLATION
(1) Position the power seat switch onto the out-
board seat cushion side shield.
(2) Install and tighten the screws that secure the
power seat switch to the inside of the outboard seat
cushion side shield. Tighten the screws to 1.5 N´m
(14 in. lbs.).
(3) Reconnect the power seat wire harness connec-
tor to the power seat switch connector receptacle.
(4) Position the outboard seat cushion side shield
onto the seat cushion frame
(5) Install and tighten the screws that secure the
outboard seat cushion side shield to the seat cushion
frame. Tighten the screws to 1.5 N´m (14 in. lbs.).
(6) Reconnect the battery negative cable.
MEMORY SET SWITCH
DESCRIPTION
Vehicles equipped with the memory system have a
memory switch mounted to the driver side front door
trim panel. This switch is used to set and recall all of
the memory system settings for up to two drivers.
The memory switch is a resistor multiplexed unit
that is hard wired to the Body Control Module
(BCM). The BCM sends out the memory system set
and recall requests to the other electronic modules
over the Programmable Communications Interface
(PCI) data bus.
The memory switch cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced. For
complete circuit diagrams, refer toWiring Dia-
grams.
OPERATION
The memory switch has three momentary switch
buttons labeled Set, 1 and 2. The Driver 1 and Driver
2 buttons are back-lit with Light-Emitting Diodes
(LED) for visibility, and are also color-coded to coin-
cide with the color-coded Driver 1 and Driver 2
Remote Keyless Entry (RKE) transmitters. The
Driver 1 memory switch button and RKE transmitter
are black, and the Driver 2 memory switch button
and RKE transmitter are gray. The memory switch
Set button also has an LED that will illuminate and
flash to indicate that the memory system is in the set
mode. This LED will automatically be extinguished
when a set request has been successfully completed.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the memory switch.
DIAGNOSIS AND TESTING - MEMORY SWITCH
For complete circuit diagrams, refer toWiring
Diagrams.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the driver side front door trim panel
switch bezel. Using a small thin bladed pry tool, gen-
tly pry the switch bezel away from the door trim
panel.
(3) Disconnect the memory switch wire harness
connector from the memory switch.
(4) Use an ohmmeter to test the resistances of the
memory switch in each switch position. See the Mem-
ory Switch Test chart. If OK, refer toMemory Sys-
temin the Diagnosis and Testing section of this
group. If not OK, replace the faulty memory switch.
MEMORY SWITCH TEST
MEMORY
SWITCH
POSITIONRESISTANCE
BETWEEN
PINSRESISTANCE
RANGE
(OHMS)
NEUTRAL 1&2 24560   1%
(24.56 k)
MEMORY 1 1&2 6830   1%
(6.83 k)
MEMORY 2 1&2 2090   1%
(2.09 k)
SET 1&2 4490   1%
(4.49 k)
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the front door trim panel switch bezel
from the driver side front door. Using a thin flat-
bladed pry tool, gently pry the switch bezel away
from the drivers door trim panel.
(3) Disconnect the memory switch wire harness
connector from the memory switch.
(4) Remove the two screws that secure the memory
switch to the back of the driver side front door trim
panel switch bezel.
(5) Remove the memory switch.
INSTALLATION
(1)Position the memory switch and install and
tighten the two screws that secure the memory switch
to the back of the driver side front door trim panel
switch bezel. Tighten the screws to 2.2 N´m (20 in. lbs.).
(2) Reconnect the memory switch wire harness
connector to the memory switch.
(3) Install the trim panel switch bezel onto the
driver side front door.
(4) Reconnect the battery negative cable.
8N - 54 POWER SEATSRS
DRIVER SEAT SWITCH (Continued)
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REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) On models with the eight-way power seat sys-
tem only, using a push pin remover or another suit-
able wide flat-bladed tool, gently pry the power seat
and power recliner switch knobs off of the switch
stems (Fig. 7).
(3) Remove the screws that secure the outboard
seat cushion side shield to the seat cushion frame.
Refer to the Body section of the service manual for
the procedure.
(4) Pull the outboard seat cushion side shield away
from the seat cushion frame far enough to access the
power seat switch wire harness connector.
(5) Disconnect the power seat wire harness connec-
tor from the power seat switch connector receptacle.
(6) Remove the screws that secure the power seat
switch to the inside of the outboard seat cushion side
shield.(7) Remove the power seat switch from the out-
board seat cushion side shield.
INSTALLATION
(1) Position the power seat switch onto the out-
board seat cushion side shield.
(2) Install and tighten the screws that secure the
power seat switch to the inside of the outboard seat
cushion side shield. Tighten the screws to 1.5 N´m
(14 in. lbs.).
(3) Reconnect the power seat wire harness connec-
tor to the power seat switch connector receptacle.
(4) Position the outboard seat cushion side shield
onto the seat cushion frame
(5) Install and tighten the screws that secure the
outboard seat cushion side shield to the seat cushion
frame. Tighten the screws to 1.5 N´m (14 in. lbs.).
(6) Reconnect the battery negative cable.
RECLINER MOTOR
DESCRIPTION
The eight-way power seat option includes an elec-
trically operated seat back recliner mechanism. The
only visible evidence of this option is the separate
power seat recliner switch control knob that is
located on the outboard seat cushion side shield, just
behind the other power seat switch control knob.
The power seat recliner unit is mounted in the
place of a seat hinge on the outboard side of the seat
(Fig. 8). The upper hinge plate of the power seat
recliner mechanism is secured with screws to the
seat back frame and is concealed beneath the seat
back trim cover and padding. The lower hinge plate
and the motor and drive unit of the power seat
recliner mechanism is secured with screws to the
seat cushion frame, and is concealed by the outboard
seat cushion side shield.
The power seat recliner cannot be repaired. If the
unit is faulty or damaged, it must be replaced. Refer
toBucket Seat Reclinerin Body for the service
procedure.
OPERATION
The power seat recliner includes a reversible elec-
tric motor that is secured to the lower hinge plate of
the recliner unit. The motor is connected to a gearbox
that moves the upper hinge plate of the power seat
recliner through a screw-type drive unit. The driver
side power seat recliner motor used on models
equipped with the optional memory system also has
a position potentiometer integral to the motor assem-
bly, which electronically monitors the motor position.
Fig. 6 Seat Switch Pin Call-Out
Fig. 7 REMOVING SWITCH CONTROL KNOBS
8N - 56 POWER SEATSRS
PASSENGER SEAT SWITCH (Continued)
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DIAGNOSIS AND TESTING - POWER SEAT
RECLINER
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.
Actuate the power seat recliner switch to move the
power seat recliner adjuster in each direction. The
power seat recliner adjuster should move in both
directions. If the power seat recliner 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 recliner adjuster still
fails to operate in only one direction, refer toPower
Seat Switchin the Diagnosis and Testing section of
this group. If the power recliner adjuster fails to
operate in either direction, perform the following
tests. For complete circuit diagrams, refer toPower
Seatin Wiring Diagrams.
(1) Check the power seat circuit breaker under the
seat. If OK, go to Step 2. If not OK, replace the
faulty power seat circuit breaker.
(2) Check for battery voltage at the power seat cir-
cuit breaker under the seat. If OK, go to Step 3. If
not OK, repair the open fused B(+) circuit to the fuse
in the Intelligent Power Module as required.
(3) Remove the outboard seat cushion side shield
from the seat. Disconnect the seat wire harness con-
nector from the power seat switch connector recepta-
cle. Check for battery voltage at the fused B(+)
circuit cavity of the power seat wire harness connec-
tor for the power seat switch. If OK, go to Step 4. If
not OK, repair the open fused B(+) circuit to the
power seat circuit breaker under the seat as
required.
(4) Check for continuity between the ground cir-
cuit cavity of the power seat wire harness connector
for the power seat switch and a good ground. There
should be continuity. If OK, go to Step 5. If not OK,
repair the open ground circuit to ground as required.
(5) Test the power seat switch. Refer toPower
Seat Switchin the Diagnosis and Testing section of
this group. If the switch tests OK, test the circuits of
the power seat wire harness between the power seat
recliner adjuster motor and the power seat switch for
shorts or opens. If the circuits check OK, replace the
faulty power seat recliner unit. If the circuits are not
OK, repair the power seat wire harness as required.
Fig. 8 Power Seat Recliner and Track - Typical
1 - SEAT BACK FRAME
2 - SEAT CUSHION PAD
3 - POWER RECLINER
4 - SEAT CUSHION FRAME
5 - SHIELD
6 - POWER SEAT TRACK ADJUSTER
RSPOWER SEATS8N-57
RECLINER MOTOR (Continued)
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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
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