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POWER SEAT SYSTEM
Power Seat System
Driver and passenger power front seats are an available factory-installed option for this vehicle. The power seat system option allows the driver and front seat passenger to electrically adjust their seat/ng positions for optimum control and comfort using the power seat switches located on the outboard seat cushion side shield of each front seat. The power seat system receives battery current through a fuse in the Power Distribution Center (PDC) and a circuit breaker in the junction block so that the power seats remain operational, regardless of the ignition switch position.

Four power seat options are offered on this vehicle, depending upon the model. They are as follows:
- Six-way power drivers seat with manual passenger seat - This power seat package is an option on Laredo models equipped with cloth- trimmed seats and includes a six-way adjustable driver seat track with manual seat back recliners.
- Six-way power driver and passenger seat - This power seat package is an option on Laredo models equipped with cloth or leather-trimmed seats and includes six-way adjustable seat tracks with manual seat back recliners. Heated Seats are available on leather-trimmed seats.
- Ten-way power drivers seat with Memory and Six-way power passenger seat - This power seat package is standard on Limited models. This option includes a six-way adjustable seat track with power seat back recliners and power lumbar supports for the driver and six-way only for the passenger.
- Ten-way power drivers and passenger seats with Memory - This power seat option is standard on Overland models and optional on Limited models. This option includes a six-way adjustable seat cushion track with power seat back recliners and power lumbar supports. Heated Seats are standard with this option.

Refer to Heated Seat System for more information on the heated seat option. Refer to Memory System in the Memory System section of this group for more information on the memory system.

The power seat system includes the following components:
- Power lumbar adjuster (ten-way power seat only)
- Power lumbar switch (ten-way power seat only)
- Power seat recliner (ten-way power seat only)
- Power seat switch
- Power seat track.

Refer to Power Seat in Wiring Diagrams for complete circuit diagrams. Following are general descriptions of the major components in the power seat/ memory seat system.

The power seat system allows the driver and/or front passenger seating positions to be adjusted electrically 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.

Memory System
An electronic memory system is standard equipment on the Limited model. 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 connected to the Programmable Communications Interface (PCI) data bus network, the memory system is also able to store and recall up to twenty - ten AM and ten FM - 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 twenty preset stations.

The memory system will automatically return to all of these settings when the corresponding numbered and color-coded button (Driver 1 - Black, or Driver 2 - Gray) of the memory switch on the driver side front door trim panel is depressed, or when the doors are unlocked using the corresponding numbered and color-coded (Driver 1 - Black, or Driver 2 - Gray) Remote Keyless Entry (RKE) transmitter. A customer programmable feature of the memory system allows the RKE recall of memory features to be disabled in cases where there are more than two drivers of the vehicle.

The memory system also has a customer programmable easy exit feature that will move the driver seat rearward 55 millimeters (two inches) or to the end of its travel, whichever occurs first, when the key is removed from the ignition switch lock cylinder.

A Memory Seat Module (MSM) or Memory Heated Seat Module (MHSM) are used on this model to control and integrate the many electronic functions and features included in the memory system. On vehicles equipped with the heated seat system option, the MHSM also controls the functions and features of that system.

The memory system includes the following components:
- Memory seat module (or memory heated seat module)
- Memory switch
- Position potentiometers on both outside power mirrors
- Position potentiometers on the driver side power seat track and power seat recliner motors.
- Radio receiver (if PCI data bus capable).

Certain functions and features of the memory system rely upon resources shared with other electronic modules in the vehicle over the Programmable Communications Interface (PCI) data bus network. The PCI data bus network allows the sharing of sensor information. This helps to reduce wire harness complexity, 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 capabilities. For diagnosis of these electronic modules or of the PCI data bus network, the use of a DRB scan tool and the proper Diagnostic Procedures are recommended.

The other 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.
- Driver Door Module (DDM) - Refer to Door Module in Electronic Control Modules for more information.
- Electronic Vehicle Information Center (EVIC) - Refer to Electronic Vehicle Information Center in Overhead Console Systems for more information.
- Passenger Door Module (PDM) - Refer to Door Module in Electronic Control Modules for more information.
- Powertrain Control Module (PCM) - Refer to Powertrain Control Module in Electronic Control Modules for more information.
- Radio Receiver - Refer to Radio Receiver in Audio Systems for more information.

Refer to Heated Seat System for more information on this system. Refer to Remote Keyless Entry System in Power Lock Systems for more information on the RKE system. Refer to Power Mirror in Power Mirror Systems for more information on the mirror position potentiometers. Refer to Power Seat Track and Power Seat Recliner in the Power Seat System section of this group for more information on the driver side power seat position potentiometers.

Refer to Power Seat in Wiring Diagrams for complete circuit diagrams. Following are general descriptions of the remaining major components in the factory-installed memory system.

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 DRB scan tool and the proper Diagnostic Procedures are recommended.

Driver And Passenger Door Modules
The Driver Door Module (DDM) monitors the memory switch through a hard wired circuit. It also monitors the unlock messages from the Remote Keyless Entry (RKE) receiver in the Passenger Door Module (PDM) sent over the Programmable Communications Interface (PCI) data bus. The DDM is programmed to send memory recall messages and memory system status messages over the PCI data bus to the other electronic modules when it detects a memory recall request.

Refer to Door Module in Electronic Control Modules for more information on the DDM and PDM.

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 provides the user with the means for enabling and disabling the many customer programmable features available on the vehicle, including those for the memory system.

See the owner's manual in the vehicle glove box for more information on the features, use and operation of the EVIC. Refer to Electronic Vehicle Information Center in Overhead Console Systems for more information on the EVIC.

MEMORY SEATS
The memory system consists of the driver power seat, both outside rear view mirrors and the radio presets. The memory module for the seat is mounted under the driver's seat. The module is available with or without the heated seat feature. The seat module receives input from the 8-way power seat switch, the driver's seat position sensors, both front seat Negative Temperature Coefficients (NTC's) (if heated seat equipped) and the PCI bus circuit. The memory switch, located on the driver door, is wired directly to the driver door module and sends its messages over the PCI bus. The memory seat module performs the following functions: positions the drivers seat, actuates the driver's and passenger's seat heaters (if equipped) and sends the memory location over the PCI bus.

When a memory button is pressed (# 1 or # 2) on the memory switch, the driver door module sends a recall message to the Memory Seat Module (MSM), the PCI radio and the passenger door module. They will in turn position the driver seat, both mirrors and set the radio presets. When the RKE button is pressed, depending on which transmitter (# 1 or # 2), the passenger door module sends the recall message.

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 MSM with two circuits. Each circuit is switched between battery and ground. By alternating the circuits the MSM controls the movement of the motors based on input from the seat mounted switch.

Each motor contains a potentiometer to monitor the seat position. To monitor the position of the motor, the MSM 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 MSM monitors the voltage change through the sensor on a separate signal circuit.

The MSM stores the input value of each of the four seat potentiometers in memory when the system is requested. The driver can initiate memory recall, using either the memory switch or the RKE transmitter. When initiated, the MSM adjusts the four seat motors to match the memorized seat position data.

For safety reasons, the memory seat recall is disabled by the MSM when the vehicle is out of park position or if the seatbelt is buckled. 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 MSM which would then flag a trouble code and the corresponding seat output would be deactivated. However, if the object obstructing the seat is removed, the seat will function normally again.

Easy Exit Seat (Available With Memory Seat)
The intent of this feature is to allow for easier entry and exit to the vehicle by moving the seat rearward a short distance when the operator turns the vehicle OFF. The seat can be recalled to one of it's two set memory positions by pressing either of the memory recall buttons on the switch or the RKE transmitters. If any seat movement is initiated, whether manual or by memory recall, after the ignition has been turned OFF, this will cancel any ensuing glide to enter movement until the next ignition cycle.

This feature can be enabled/disabled by the owner through the electronic vehicle information center (EVIC) or using the DRB III. When using the DRB III it will also inform as to what state it is in. To reinstate the feature, simply repeat the process.

Guard Bands
The module provides guard bands which prevent the seat track from hitting the hard limits of the given seat axis during manual power seat operation. The guard band values for each hard limit are stored in EEPROM. The guard band can be bypassed by running the seat to the end of its travel and then releasing the switch and pressing it again. The seat will move a short distance further. Once the seat is past the guard band, it can be stored in memory, but if recall is initiated the seat will move to the guard bands and no further.

When a seat module or seat track assembly is replaced, the DRB III must be used to perform the "Reset Guard Bands" procedure.WARNING: The operator must be out of the seat when this procedure is being used as the seat will move to the end of it's travel in all 8 positions.

Electrically Heated Seats
The heated seat feature is available with or without the memory system. The module is located under the driver's seat and is known as the Heated Seat Module (HSM) or the Memory Heated Seat Module (MHSM). The control switches for the heated seats are located on the instrument panel and are wired to the body control module. The BCM then sends the message to the HSM via the PCI bus. The system offers two seat temperature settings of approximately 96.8 F (36 °C) (LO) and approximately 107.6 F (41 °C) (HI).

As the temperature in the seat rises, the negative temperature coefficient (NTC) resistance decreases and the voltage reading detected by the HSM decreases. The seat heater output is deactivated once the voltage reading reaches it's threshold for either setting, high or low.

As the temperature decreases, the voltage reading increases until the upper threshold is reached for either setting high or low. At this point the seat heat output is activated once again and this cycle repeats itself as long as the seat heat request is on.

The thresholds for low and high settings are preprogrammed into the module memory.

The heated seat switch contain resistors pulled up to 5 volts which are processed by the body control module as the voltage readings indicating desired heat setting high or low.

The heater elements inside the seat back and cushion are different for the Limited and Laredo models. The Laredo seat heater elements are wired in series whereas the Limited seat elements are wired in parallel. This means that if an element is open in a Laredo model there will be no heater output to either the cushion or the seat back. If an element is open in a Limited model, the other elements will operate as usual. However, if one of the elements is open, the seat cushion will have to be replaced.

There are three heater elements in the seat cushions for both models. The Laredo uses a resistor wire for its center and both side bolsters (raised outer side panels) and the Limited uses a carbon fiber element for its center and resistor wire for the bolsters.