Seats: Description and Operation
POWER SEAT SYSTEMThe 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.
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 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 Memory 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 MINUTES FOR THE SYSTEM CAPACITOR TO DISCHARGE 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, six-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 Seat Recliner - Two power seat recliners 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 diagrams. Following are general descriptions and operations for the major components in the power seat and memory seat systems.
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 operational, 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.
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 Programmable Communications Interface (PCI) data bus network, 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 preset 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 feature of the overhead console. Refer to the Overhead Console section of this manual for additional information.
The memory system also has a easy exit feature that will move the driver seat rearward 55 millimeters 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 feature of the overhead console. Refer to the Overhead Console section of this manual for additional information.
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 components:
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 manual 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 programmed into the memory system also. Refer to the Audio section of this manual for additional information.
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 manual are recommended.
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 information on the heated seat system.
Refer to Wiring for complete circuit diagrams. Following are general descriptions and operations of the major components in the power/memory seat systems.
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 reading 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 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. These inputs are monitored over the PCI data bus circuit by the BCM.
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.