Seats: Description and Operation

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 seating 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.

Two power seat options are offered on this vehicle, depending upon the model. They are as follows:
- Six-way power seat - This power seat is an available option on Laredo models equipped with cloth-trimmed seats and includes a six-way adjustable seat cushion track with manual seat back recliners.
- Ten-way power seat - This power seat option is standard on Limited models and optional on Laredo models with leather-trimmed seats. This option includes a six-way adjustable seat cushion track with power seat back recliners and power lumbar supports.

The ten-way power seat is also available with the heated seat system option on both Laredo and Limited models; and, on Limited models only, there is a standard equipment memory system that automatically positions the power seat for two different drivers.

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.

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.

POWER LUMBAR ADJUSTER

Power Lumbar Adjuster:

The ten-way power seat option includes an electrically operated lumbar support mechanism. The only visible evidence of this option is the separate power lumbar switch control paddle that is located on the outboard seat cushion side shield, just forward of the other power seat switch control knobs. The power lumbar adjuster and motor are concealed beneath the seat back trim cover and padding, where they are secured to a molded plastic back panel and to the seat back frame.

The power lumbar adjuster cannot be repaired, and is serviced only as a unit with the seat back frame. If the power lumbar adjuster or the seat back frame are damaged or faulty, the entire seat back frame unit must be replaced.

The power lumbar adjuster mechanism includes a reversible electric motor that is secured to the inboard side of the seat back panel and is connected to a worm-drive gearbox. The motor and gearbox operate the lumbar adjuster mechanism in the center of the seat back by extending and retracting a cable that actuates a lever. The action of this lever compresses or relaxes a grid of flexible slats. The more this grid is compressed, the more the slats bow outward against the center of the seat back padding, providing additional lumbar support.

POWER LUMBAR SWITCH
The ten-way power seat option includes an electrically operated lumbar support mechanism. A single two-way momentary power lumbar switch is located on the outboard seat cushion side shield of each front seat, just forward of the other power seat switches. The power lumbar switch is secured to the back of the seat cushion side shield with two screws, and the switch paddle protrudes through a hole to the outside of the shield. The switch paddle is located in a shallow depression molded into the outer surface of the seat cushion side shield that helps to shroud it from unintentional actuation when entering or leaving the vehicle.The power lumbar switches cannot be adjusted or repaired and, if faulty or damaged, they must be replaced.

when the power lumbar switch paddle is actuated, a battery feed and a ground path are applied through the switch contacts to the power lumbar adjuster motor. The motor operates to move the lumbar adjuster through its drive unit in the selected direction until the switch is released, or until the travel limit of the adjuster is reached. When the switch is moved in the opposite direction, the battery feed and ground path to the motor are reversed through the switch contacts. This causes the motor to run in the opposite direction.

The power lumbar switch should not be held applied in either direction after the adjuster has reached its travel limit. The power lumbar adjuster motor contains a self-resetting circuit breaker to protect it from overload. However, consecutive or frequent resetting of the circuit breaker must not be allowed to continue, or the motor may be damaged.

POWER SEAT RECLINER
The ten-way power seat option includes an electrically 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 switch is integral to the ten-way power seat switch unit, but is actuated with a separate switch knob.

Power Seat Recliner And Track:

The power seat recliner unit is mounted in the place of a seat hinge on the outboard side of the seat. The upper hinge plate of the power seat recliner mechanism is secured with two 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 two 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.

The power seat recliner includes a reversible electric 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 assembly, which electronically monitors the motor position.

POWER SEAT SWITCH

Six-Way Power Seat Switches:

Ten-Way Power Seat Switches:

Two different power seat switches are used on this vehicle, depending upon the optional power seat system installed in the vehicle. The six-way power seats are each equipped with a switch featuring three switch control knobs ganged together on the outboard seat cushion side shield. The ten-way power seats are each equipped with a switch featuring two knobs ganged together on the outboard seat cushion side shield.

The switch units for both power seat types are secured to the back of the seat cushion side shield with two screws. However, the control knobs for the six-way power seat switch unit remain installed during switch unit removal and installation, while both knobs for the ten-way power seat switch unit must be removed.

The individual switches in both power seat switch units cannot be repaired. If one switch is damaged or faulty, the entire power seat switch unit must be replaced.

The power seat tracks of both the six-way and the ten-way power seat systems can be adjusted in six different ways using the power seat switches. The ten-way system has the additional power seat recliner switch integral to the power seat switch and also has a separate, stand-alone switch to control the power lumbar adjuster. 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 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 direction until the switch is released, or until the travel limit of the adjuster is reached. When the switch is moved in the opposite direction, the battery feed and ground path to the motor are reversed through the switch contacts. This causes the adjuster motor to run in the opposite direction.

No power seat switch should be held applied in any direction after the adjuster has reached its travel limit. The power seat adjuster motors each contain a self-resetting circuit breaker to protect them from overload. However, consecutive or frequent resetting of the circuit breaker must not be allowed to continue, or the motor may be damaged.

POWER SEAT TRACK
Both the six-way and the ten-way power seat options include a single electrically operated power seat track unit located under each front bucket seat. 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 screws to the floor panel seat cross member, and at the rear with two screws 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.

Power Seat Track - Typical:

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 gear- boxes 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, tilting the 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.

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 Pd 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.
- Driver Door Module (DDM) - Refer to Door Module in the Power Lock System.
- Electronic Vehicle Information Center (EVIC) - Refer to Electronic Vehicle Information Center.
- Passenger Door Module (PDM) - Refer to Door Module in the Power Lock System
- Powertrain Control Module (PCM) - Refer to Powertrain Control Module
- Radio Receiver - Refer to Radio Receiver.

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.

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.

MEMORY SEAT MODULE
All Limited models are equipped with a standard memory system. However, there are two versions of the Memory Seat Module (MSM). The standard version of the MSM is used on vehicles that are not equipped with the optional heated seat system. A Memory Heated Seat Module (MHSM) is used on vehicles that are equipped with the heated seat system option. A third module, the Heated Seat Module (HSM), does not have any memory system capabilities and is only available on Laredo models that are equipped with an optional heated seat system.

All three modules are packaged in an identical molded plastic housing which is mounted on a bracket that is located between the power scat track and the seat cushion frame under the forward edge of the driver side front seat cushion. The MSM or MHSM is used to control all of the driver side power seat memory functions and features. The MSM or MHSM contains a central processing unit and interfaces with other electronic modules in the vehicle on the Programmable Communications Interface (PCI) data bus network.

For diagnosis of the MSM, MHSM or the PCI data bus, a DRB scan tool and the proper Diagnostic Procedures are recommended. The MSM or MHSM cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

The MSM receives hard wired inputs from the power seat switch and the potentiometers on each of the driver side power seat motors. The MSM receives messages over the PCI data bus from the Driver Door Module (DDM) (memory switch status), the Powertrain Control Module (PCM) (vehicle speed status), and the Body Control Module (seat belt switch status). The programming in the MSM allows it to process the information from these inputs and send control outputs to each of the driver side power seat motors. The MSM will prevent the seat memory recall function from being initiated if the driver side seat belt is buckled, if the transmission gear selector lever is not in the Park or Neutral positions, or if the vehicle is moving.

MEMORY SWITCH
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 Driver Door Module (DDM), which is also located on the driver side front door trim panel. The DDM 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.

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 coincide 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. For diagnosis of the memory switch, the DDM or the PCI data bus, the use of a DRB scan tool and the proper Diagnostic Procedures are recommended.