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.

A driver side 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 mem-
ory seat system that automatically positions the
power seat for two different drivers. Refer to Heated
Seat System for more information on the heated
seat option. Refer to Memory System in the Mem-
ory System section of this group for more information
on the memory system.

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.

The power seat system for this vehicle includes the

following major components, which are described in
further detail later in this section:

• Power Seat Track - Two power seat tracks are

used per vehicle. One seat track is used for each
front seat. Depending on the seat track, four-way or
eight-way power, the track may be equipped with up
to four electric motors. Refer to power seat track
later in this section for additional information.

POWER SEATS

8N - 11

• Power Seat Recliner - Two power seat reclin-

ers are used per vehicle. One seat recliner is used for
each front seat. The power seat recliner replaces the
manual seat recliner found on low-line LH vehicles.
Refer to power seat recliner later in this section for
additional information.

• Power Seat Switches - Two power seat

switches are used per vehicle. One seat switch is
used for each front seat. Each switch is mounted in
the appropriate seat cushion side shield. Refer to the
appropriate power seat switch later in this section for
additional information.

Refer to Wiring Diagrams for complete circuit dia-

grams. Following are general descriptions and opera-
tions for the major components in the power seat and
memory seat systems.

DESCRIPTION - MEMORY SEAT SYSTEM

An electronic memory seat system is available on

some LH models. The memory system is able to store
and recall all driver side power seat positions, and
the drivers side view mirror positions. The system
can be set for two different drivers. On vehicles with
a factory installed radio connected to the Program-
mable Communications Interface (PCI) data bus net-
work, the memory system is also able to store and
recall up to twenty radio station presets (ten AM and
ten FM), also 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 twenty pre-
set stations.

The memory system will automatically recall all of

these settings when a button of the memory switch is
depressed, or when the doors are unlocked using the
Remote

Keyless

Entry

(RKE)

transmitter

(if

enabled). If the vehicle has more than two drivers
the RKE transmitter recall of memory features can
be disabled. This is a customer programmable fea-
ture of the overhead console. Refer to the Overhead
Console section of this manual for additional infor-
mation.

The memory system also has a easy exit feature

that will move the driver seat rearward 55 millime-
ters or to the end of its travel, whichever occurs first,
when the key is removed from the ignition switch
lock cylinder. This is a customer programmable fea-
ture of the overhead console. Refer to the Overhead
Console section of this manual for additional infor-
mation.

A Memory Heated Seat Mirror Module (MHSMM)

is used to control and integrate the many electronic
functions and features included in the memory seat/
mirror and heated seat systems.

The memory system includes the following compo-

nents:

• Memory

Heated

Seat

Mirror

Module

(MHSMM) - This module contains the solid state
electronic control and diagnostic logic circuitry for
the heated seat and memory seat/mirror systems.
One module is used per vehicle and is mounted
under the drivers front seat cushion. Refer to the
Electronic Control Module section of this manual for
additional information.

• Memory Set/Selector Switch - One switch is

used per vehicle and is mounted in the drivers seat
cushion side shield. Refer to the Memory Set Switch
later in this section of this manual for additional
information.

• Position Potentiometers - Drivers Mirror -

The potentiometer is permanently installed on the
drivers side view mirror motor. This potentiometer is
used to provide a reference signal to the memory
heated seat mirror module, letting the module know
the exact position of the mirror.

• Position Potentiometers - Seat Track -

These potentiometers are permanently installed in
each of the power seat track motors. They are used
to provide a reference signal to the memory heated
seat mirror module, letting the module know the
exact position of the seat cushion and recliner. Refer
to Power Seat Track later in this section of the man-
ual for additional information.

• RKE Transmitter - The RKE transmitter is

attached to the key ring supplied with the vehicle.
This device is used to recall preset memory positions
as well as other features. Refer to the Power Locks
section of this manual for additional information.

• Radio Receiver - The radio is also part of the

memory system and if the radio is PCI data bus
capable, multiple radio station presets can be pro-
grammed into the memory system also. Refer to the
Audio section of this manual for additional informa-
tion.

Certain functions and features of the memory sys-

tem rely upon resources shared with other electronic
modules in the vehicle over the Programmable Com-
munications Interface (PCI) data bus network. The
PCI data bus network allows the sharing of sensor
information. This helps to reduce wire harness com-
plexity, internal controller hardware, and component
sensor current loads. At the same time, this system
provides increased reliability, enhanced diagnostics,
and allows the addition of many new feature capabil-
ities. For diagnosis of these electronic modules or of
the PCI data bus network, the use of a DRB

t scan

tool and the proper Diagnostic Procedures manual
are recommended.

8N - 12

POWER SEATS

POWER SEATS (Continued)

Other vehicle equipped electronic modules that

may affect memory system operation are as follows:

• Body Control Module (BCM) - Refer to Body

Control Module in Electronic Control Modules for
more information.

• Electronic

Vehicle

Information

Center

(EVIC) - Refer to Electronic Vehicle Information
Center in Overhead Console for more information.

• Powertrain Control Module (PCM) - Refer to

Powertrain Control Module in Electronic Control
Modules for more information.

Refer to Heated Seat System for more informa-

tion on the heated seat system.

Refer to Wiring for complete circuit diagrams. Fol-

lowing are general descriptions and operations of the
major components in the power/memory seat sys-
tems.

OPERATION

OPERATION - POWER SEAT SYSTEM

The power seat system receives battery current

through a 40 amp fuse in the Power Distribution
Center (PDC) and a 20 amp circuit breaker in the
junction block so that the power seats remain opera-
tional, regardless of the ignition switch position. 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 SEAT SYSTEM

The Memory Heated Seat/Mirror Module receives

hard wired inputs from the memory set/position
switch and the potentiometers, mounted on each of
the driver power seat track motors and the driver
side view mirror motor. The programmed software in
the module allows it to know where the seat/mirror
is located in its designed travel by a resistance read-
ing generated from the seat track or mirror mounted
potentiometer. This way, when the memory switch is
depressed the module will power the seat track or
mirror motors until the correct preset location is
achieved. The module will prevent the seat memory
recall function from being initiated, if the transmis-
sion gear selector lever is not in the Park or Neutral
positions, or if the vehicle is moving. These inputs
are monitored over the PCI data bus circuit by the
MHSMM.

See the owner’s manual in the vehicle glove box for

more information on the features, use and operation
of the memory seat system. Refer to Electronic
Vehicle Information Center in Overhead Console
Systems for information on the EVIC.

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING - POWER SEATS

The following tests will help to diagnose the hard

wired components and circuits of the power seat sys-
tem. 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.

WARNING: SOME VEHICLES ARE EQUIPPED WITH
SEATBACK

MOUNTED

AIRBAGS.

BEFORE

NOTE: Vehicles equipped with the memory/heated
seat option utilize a low voltage cut-off feature. This
feature turns off the 12v power to the power seat
system anytime vehicle voltage is below 11.7v. Be
certain to check the vehicle electrical system for
proper voltage anytime the power seat system
appears inoperational.

The most reliable, efficient, and accurate means to

diagnose the driver side power seat with the memory
system option requires the use of a DRB III

t scan

tool and the proper Diagnostic Procedures manual.
The DRB III

t scan tool can provide confirmation that

the PCI data bus is functional, that all of the elec-
tronic modules are sending and receiving 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 outputs to perform its
driver side power seat functions.

Before any testing of the power seat system is

attempted, the battery should be fully-charged. For
complete circuit diagrams, refer to Power Seat in
the Contents of 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

POWER SEATS

8N - 13

POWER SEATS (Continued)

the dome lamp does not dim, proceed with testing of
the individual components and circuits.

TESTING VOLTAGE TO SEAT

The following test will determine whether or not

voltage is continuous through the body harness to
the seat switch.

(1) Remove the front seat cushion side shield from

the seat to be tested. Refer to Body for the procedure.

(2) Using a voltmeter, connect the ground lead to

Pin 5 and positive lead to Pin 1 of the seat switch
connector. If battery voltage is present circuit is OK.
If no voltage is present check circuit breaker and
repair as necessary.

TESTING CIRCUIT BREAKER

Find correct circuit breaker in junction/fuse block.

Pull out slightly but be sure that circuit breaker ter-
minals still contact terminals in fuse block. Connect
ground wire of voltmeter to a good ground. With
probe of voltmeter positive wire, check both termi-
nals of circuit breaker for battery voltage. If only one
terminal checks at battery voltage, circuit breaker is
defective and must be replaced. If neither terminal
shows battery voltage, check for open or shorted cir-
cuit to circuit breaker.

DIAGNOSIS AND TESTING - MEMORY SEAT
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 III

t scan tool and the proper Diagnostic Proce-

dures manual. The DRB III

t scan 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.

STANDARD PROCEDURE - MEMORY SYSTEM
PROGRAMMING

The

Memory

Heated

Seat

Mirror

Module

(MHSMM) interfaces with the RKE vial the Pro-
grammable Communication Interface (PCI) bus. The
proper procedure of setting and recalling a memory
position using the RKE is as follows:

(1) Press memory switch 1 and release to recall

memory position 1.

(2) Adjust the seat, recliner, set radio station pre-

sets and side view mirrors to the desired position.

(3) Press momentarily and release memory switch

(4) Press momentarily and release memory switch

1 or 2.

(5) Press and release the LOCK button on one of

the RKE transmitters. Do NOT press any switch for
10 seconds.

To program the second driver’s position, repeat the

above procedure using memory switch 2. The second
RKE transmitter can be programmed in the same
fashion.

NOTE: The module will abort a recall if the trans-
mission is moved out of park or if any seat move-
ment is activated whether manually or by memory
recall.

To recall either of the programmed positions

momentarily press and release either memory selec-
tor switch 1 or 2. If using RKE, just press and
release the UNLOCK button on the proper transmit-
ter for either position 1 or 2.

A recall is possible any time the vehicle transmis-

sion is in PARK. This condition is monitored by the
MHSMM.

MEMORY SET SWITCH

DESCRIPTION

The memory set/selector switch is mounted on the

drivers seat cushion side shield (Fig. 1), within easy
reach of the driver. This switch is used to set new
and recall preset memory positions of seat, seat
recliner, and the side view mirrors.

The memory set switch cannot be repaired or

adjusted. If one switch is damaged or faulty, the
entire memory set switch must be replaced.

Fig. 1 Memory and Heated Seat Switches

1 - MEMORY SET SWITCH ASSEMBLY
2 - MEMORY SET BUTTON
3 - HEATED SEAT SWITCH
4 - LED’S
5 - MEMORY POSITION SELECT BUTTONS

8N - 14

POWER SEATS

POWER SEATS (Continued)

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