Seats: Description and Operation
Seats
COMPONENT LOCATION
OVERVIEW
Two variants of driver and passenger front seats are available:
- Low line seat with 8-way adjustment
- High line seat with 10-way adjustment.
The front seats are fitted with the seat belt bolted to the seat rail. The frames are common to both variants and are equipped with the following:
- Seat control switches
- Cushion front height adjustment
- Cushion rear height adjustment
- Cushion front tilt adjustment (high line only)
- Backrest adjustment
- Head restraint adjustment
- Lumbar adjustment
- Seat forward and rearward adjustment
- Side air bag module
- Backrest heating
- Cushion heating
- Seat climatic control (available as an option on the high line version).
WARNING: Prior to removal of the front seats and before disconnecting the front seat wiring harness electrical connectors (which includes the side air bag module electrical connectors), the battery ground cable should be disconnected and a period of at least 1 minute allowed to elapse. The same amount of care should be taken when handling and storing the front seats, as would be taken when handling and storing air bag modules.
Both variants of the front seats are fitted with a manually adjustable folding armrest on the inboard side of the seat. The memory recall functions are also available on higher specification vehicles.
The driver and passenger front seats, although almost identical, have some unique components:
- The front driver seat has a seat position sensor
- The front passenger seat on North American Specification (NAS) vehicles have a seat occupant classification system
- The front passenger seat on Rest Of the World (ROW) vehicles, except Australia, has a seat occupancy detection system.
The occupant classification system and the seat occupancy detection system both form an integral part of the Supplemental Restraint System (SRS). For additional information, refer to Air Bag Systems Description and Operation
The rear bench seats are designed to fold forward to increase the rear load space. a 60:40 split gives the owner increased flexibility when loading the vehicle with large objects. All rear seats are equipped with 3-point seat belts and adjustable head restraints. The seats can also be fitted with seat cushion heaters in both outboard seats, climate control and also the following electric adjustment:
- Backrest adjustment
- Lumbar support adjustment.
Integrated Whiplash Reduction System
The integrated whiplash reduction system is incorporated into the backrest of the front seats. Head restraint forward positioning is activated by the natural occupant rearward displacement during low speed rear impacts. The head restraint forward positioning is achieved by 10.8 degrees maximum movement of an integral seat deployment paddle.
FRONT SEAT CONTROLS
NOTE:
Hi-line version shown, lo-line similar.
The switch pack is mounted on the seat valance of the driver and passenger seats and provides movement in the following axis:
- Seat forward/rearward adjustment
- Seat height adjustment
- Seat angle adjustment
- Backrest angle adjustment
- Head restraint height adjustment (electric only on hi-line - manual on lo-line)
Electric adjustment of the seat position can be carried out at any time, having priority over memory recall. For more information regarding seat operation, refer to the owner's handbook.
FRONT SEATS
On seats with the memory function, seat position is monitored by the seat memory control module using Hall sensors incorporated into the motors. Seat memory is standard on the driver's seat and optional on the passenger seat. Each seat memory can be configured for 3 memory positions, which are set using the seat memory switch and stored in the seat memory control module.
The switches for electrically adjusting the seats are located in the seat switch pack on the seat valance. The seat memory control module is located under the seat and controls the movement of the seat via hard-wired connections to the motors.
On passenger seats without the memory function, the seat switch pack is connected directly to the seat motors.
Seat Motors
The seat motors are permanent magnet motors. Two pins within the seat switch pack control the motors. Both pins are connected to ground. Operating a switch in one direction will apply voltage to that pin while the other pin remains connected to ground. Operating the switch in the opposite direction reverses power and ground to the motor allowing the motor to run in the opposite direction.
The seats can be manually adjusted at any time. Positioning is interrupted if manual adjustment is required during automatic adjustment (memory recall). The manual adjustment is not effective before the switch is operated again.
Due to the sequential activation of the drive motors, the switch requests are prioritized in the following order:
- Forward/rearward adjustment
- Backrest
- Height
- Angle
- Head restraint
- Backrest head
- Steering column angle
- Steering column forward/rearward adjustment.
Heated Front Seats
The seat heater elements are located in the seat cushion and backrest. The cushion and backrest heater elements are wired in series. The cushion heater element has an input feed from the temperature control unit and an output to the backrest heater element, which outputs to ground.
The seat heaters are thermostatically controlled and will operate intermittently to maintain a predetermined temperature. The indicators in the switches will remain illuminated until the heaters are either manually turned off, or the starter switch is turned off.
Feedback of the seat temperature is via a NTC (negative temperature coefficient) sensor within the seat cushion. The resistance of this sensor changes with the temperature of the seat cushion allowing the ATC (automatic temperature control) module to raise or lower the voltage to the seat heater elements to raise or lower their temperature.
An ignition feed is supplied to each sensor via the relevant seat heater switch.
Operation of the heated seats is controlled by the ATC (automatic temperature control) module. Two push-button switches are mounted in the ATC (automatic temperature control) module panel. Each switch has 2 integral Light Emitting Diodes (LED) to display the level of heating selected.
Climate Front Seats
Front Seat Heating/Climate Controls
High specification vehicles are fitted with climatic seats, which are able to deliver heating and cooling to the front seat occupants. Vehicles fitted with climatic seats feature 2 additional rotary controllers mounted in the ATC (automatic temperature control) module switch pack, adjacent to the clock. The rotary controllers are used to select cooling and heating. Three levels of cooling and heating are available, dependant on the degree of controller rotation. The center of the controller is pressed once to ventilate both the seat back and cushion (both indicators on the switch will illuminate). A second press of the switch will ventilate the seat back rest only (the cushion indicator will extinguish).
Front Seat Climate Control Module
NOTE:
If climatic seats are fitted, heated seat switches are not featured on the ATC (automatic temperature control) module control panel. They are located in the lower panel, either side of the clock.
NOTE:
The ATC (automatic temperature control) module does not control any aspect of climatic seat operation.
The controlling software for the climatic seats is contained within a front seat climate module mounted on the floorpan, below the front passenger seat. When a temperature selection is made through either of the rotary seat climate controllers, the ATC (automatic temperature control) module switchpack provides a medium speed CAN (controller area network) bus message to the climate module. The climate module interprets the medium speed CAN (controller area network) bus message as a temperature value and attempts to heat or cool the seat accordingly.
Both climatic front seats contain two Peltier cells; one in the cushion, one in the backrest. The Peltier cells are able to deliver heating and cooling based on a voltage provided by the climate module. Each seat also contains a fan, which blows air over the Peltier cells to distribute heating or cooling throughout the seat. The Peltier effect occurs when an electrical current is passed through a junction formed by two dissimilar conductors, creating a heat pump. A heat pump absorbs heat from one side of the system, causing it to cool, and then transfers the heat to the other side, causing it to warm. The cell is capable of cooling the incoming air by approximately 8°C (12.4°F), which means that temperature output will depend on the ambient temperature inside the vehicle.
The climate module monitors seat heating through a NTC (negative temperature coefficient) temperature sensor. The temperature sensor is only used to monitor seat heating. Seat cooling is open loop, with no temperature signal provided back to the climate module. When a temperature selection is made through either of the rotary controllers, the ATC (automatic temperature control) module switchpack provides a medium speed CAN (controller area network) bus message to the climate module as a temperature value and attempts to heat or cool the seat accordingly.
Although the rotary control LED (light emitting diode)'s will illuminate if a selection is made when the ignition is in the on mode, the Peltier cells will not operate until the engine is running. After the ignition is in the off mode, the climate module will retain the current temperature settings for approximately 15 minutes. After this period, the seats will be set to 'off' when the ignition is in the on mode.
Front Seat Lumbar Adjustment
Lumbar adjustment is provided by an inflatable cushion with dual air cells and an air pump installed in the seat backrest. A valve block containing solenoid valves controls the inflation of the cushion in relation to switch selections made on a 4-way switch.
The 4-way switch is located on the seat switchpack and controls the operation of the backrest lumbar pump and valve block solenoids.
The lumbar pump inflates cells in a cushion in the backrest via a valve block, which provides extra support for the seat occupant. With no load on the seat it takes approximately 10 seconds to completely inflate the bladder. With a load of 25 kg (55 lb) it takes approximately 15 seconds to inflate the cushion. A pressure cut off switch in the system will operate at 0.12 to 1.93 bar (1.8 to 28 lbf.in2 ).
SEAT MEMORY CONTROL MODULE
The seat memory control module is located on the underside of the seat frame of the seat it controls. The module relies upon a number of inputs to control various outputs. As with all electronic control modules, the unit needs information regarding the current operating conditions of the engine and other related systems before it can make calculations, which determine the appropriate outputs.
The memory control module can store up to 3 different driver seating, mirror and steering column positions for each key. The passenger seat memory module only stores memory positions relating to the front passenger seat.
All memory values are stored in the non-volatile memory, EEPROM. The current motor positions, which are monitored by the seat memory control module using Hall sensors integral with the motors, are stored in the EEPROM. If a loss of power occurs, when the power supply is restored the current motor positions are recalled from the memory and adopted as the current positions. This allows the relative memory positions to be retained without any need to re-calibrate. The memory control module checks the integrity of all data stored in the EEPROM each time it exit's stand-by mode. In the event that the data is corrupt, the control module adopts the default values for all of the programming options. All memory positions are deemed as invalid and the software will perform as if there are no memory positions stored. Following the procedure for storing a memory position again will reset the relevant memory and allow full functionality.
Memory
Function
Controlled by the driver's seat memory control module, the memory function stores and recalls the position of the driver's seat, the steering column and the exterior mirrors.
The memory recall functions are:
- Forward/backward adjustment
- Seat height
- Seat angle
- Backrest angle
- External mirror adjustment
- Steering column adjustment
The seat, steering column, and exterior mirrors will move to the stored position whenever the relevant memory-recall button in pressed.
The passenger seat memory control module stores and recalls the position of the front passenger seat only. The memory recall function for the passenger seat are as follows:
- Forward/backward adjustment
- Seat height
- Seat angle
- Backrest angle.
For more information regarding the operation of the memory function, refer to the owner's handbook.
NOTE:
Seat, steering column and exterior mirror movement will be halted if any seat adjustment switch (including memory buttons) or the steering column adjustment switch is moved or pressed. To re-start movement of these, the relevant seat memory button will need to be pressed again.
On vehicles with electric rear seats, the power supplies for the seat motors are supplied via the seat memory control modules. Therefore, it is possible for a vehicle to have a non-memory passenger seat but have the seat memory control module located below it to provide power to the rear, passenger side seat motors.
Easy Entry/Exit
The 'Easy Entry/Exit' mode provides automatic movement of the steering column to allow easier entry to or exit from the vehicle.
NOTE:
If the adjustment switch is moved during entry/exit operation, steering column movement will stop.
When the ignition is in the on mode and the vehicle smart key is sensed by the Keyless Vehicle Module (KVM), the steering column, door mirrors and driver's seat will return to the stored position relating to that smart key. If, however, the memorized driver position has been changed (using the seat memory switches or another smart key transmitter), the steering wheel, door mirrors and the seat will move to the new stored memory position.
When the ignition is in the off mode, the steering column will move to the uppermost rake to allow easier exit from the vehicle cabin.
Stall Detection
Seat, steering column and mirror motors are deemed to have stalled if there is no change in the inputs that are received from the corresponding feedback sensors while that axis motor is being driven.
If a stall condition is detected, then the drive to that axis motor is cancelled for the remainder of that memory operation (memory recall) or until the switch is re-selected (manual movement).
If the motor movement has stopped due to loss of sensor feedback, either, stall or sensor failure, then that axis motor may be activated again, to move past the stall position, by re-selecting the appropriate switch. This allows control of the motor to be maintained if sensor feedback is lost.
Upon re-selection of movement, if sensor pulses are detected then the motor will continue to be driven until the switch is released or another stall condition is detected. If sensor feedback is not detected then the motor is only driven for 0.5 second and then stops until the switch is released and then pressed again, when a further 0.5 second of activation is permitted, and so on.
For all seat motor and steering column manual movements, whenever a motor is driven and a stall occurs, the seat memory control module records the position at which the stall occurred. If movement occurs beyond a stall position, then that position is erased from the seat control module's memory. This will always allow movement past a previously recorded stall position once movement has been registered beyond that position. This is the case for both manual and memory movement.
REAR SEATS
The switches for electrically adjusting the rear seat backrest are located in the rear door trims. Two versions of the switch are available; one lo-line switch with one switch for rear back rest adjustment and one switch with rear back rest adjustment, lumbar adjustment and a rotary switch for climate control. The switch corresponding to the front passenger seat is fitted with a front seat forward/backwards switch to allow for legroom adjustment.
On vehicles with non-climate, non-electric adjustment heated rear seats, the rear seat heaters are selected by switches on the rear of the floor console and controlled by the ATC (automatic temperature control) module.
On vehicles with electric adjustment, non-climate seats, the rear seat heaters and electrical adjustment are selected by switches located in the door trims.
On vehicles with electrical adjustment and climate control the climate seat controls and electrical adjustment are selected by switches located in the door trims.
On vehicles with electric and climate controlled rear seats, the power supplies for the motors and climate functions are supplied from the front seat memory control module. On vehicles with a passenger front seat without the memory function, the seat memory control module is still fitted to the front passenger seat to supply the power for the passenger side rear seat functions. The seat memory control module is connected to the rear seat control switch and controls the movement of the rear seat via hard-wired connections to the motors.
Rear Seat Control Switch
Heated Rear Seats - Non-Climate Seats
The rear seat heater elements are located in the outboard seat cushions and backrests. The cushion and backrest heater elements are wired in series. The cushion heater element has an input feed from the floor console mounted climate switch pack and an output to the backrest heater element, which outputs to ground.
The seat heaters are thermostatically controlled and will operate intermittently to maintain a predetermined temperature. The indicators in the switches will remain illuminated until the heaters are either manually turned off, or the ignition is in the off mode.
Feedback of the seat temperature is via a NTC (negative temperature coefficient) sensor within the seat cushion. The resistance of this sensor changes with the temperature of the seat cushion and a signal relating to the temperature is used to raise or lower the voltage to the seat heater elements to raise or lower their temperature.
Operation of the heated rear seat elements is controlled by the switches on the floor console climate switch pack. Two push-button seat heater switches are mounted in the switch pack. Each switch has 2 integral LED (light emitting diode)'s to display the level of heating selected. The switch can be pressed once to select the seat back rest heater or twice to select both the seat backrest heater and the seat cushion heater. The appropriate LED (light emitting diode)'s will illuminate to show which elements have been selected.
2 Zone Climate Control
The rear seat heater elements are connected directly to the climate switch pack in the floor console. The switchpack receives power supplies from the ATC (automatic temperature control) module and also supplies a rear heat temperature signal to the ATC (automatic temperature control) module. The ATC (automatic temperature control) module uses the temperature signal to regulate the power supplied to seat heater elements and control their temperature.
4 Zone Climate Control
The rear seat heater elements are connected to the climate switchpack in the floor console. The switchpack receives power supplies from the RJB (rear junction box) and it also has a LIN (local interconnect network) connection to rear ATC (automatic temperature control) module which is located under the front passenger seat. The rear ATC (automatic temperature control) module controls the power supply to the rear seat heater elements via a CAN (controller area network) message to the RJB (rear junction box) which regulates the power supplied to the rear seat heater elements and control their temperature.
Heated/Cooled Rear Climate Seats
Vehicles with rear climate seats have rotary climate controls located in the switch packs mounted in the door trim of each rear door. A rear seat climate module controls the functions of the climate seats. The heating and cooling functions of the climate rear seats operate using 2 Peltier cells; one in the seat cushion and one in the seat backrest. The climate functions of the seats are only active when the engine is running to preserve battery power.
The controlling software for the rear climate seats is contained with the rear seat climate control module, located under the RH (right-hand) side of the rear seat cushion. The module is connected to other vehicle system on the medium speed CAN (controller area network) bus. The module receives climate rotary switch temperature selections as PWM (pulse width modulation) signals and push button switch selections as ground path completions to the relative front seat memory control module. The front seat memory control module then transmits medium speed CAN (controller area network) bus messages to the rear climate module which then controls the rear seat heating/cooling Peltier cells to achieve the required seat temperature.
Rear Seat Climate Control Module
Both climatic rear seats contain two Peltier cells; one in the cushion, one in the backrest. The Peltier cells are able to deliver heating and cooling based on a voltage provided by the climate module. Each seat also contains a fan, which blows air over the Peltier cells to distribute heating or cooling throughout the seat. The Peltier effect occurs when an electrical current is passed through a junction formed by two dissimilar conductors, creating a heat pump. A heat pump absorbs heat from one side of the system, causing it to cool, and then transfers the heat to the other side, causing it to warm. The cell is capable of cooling the incoming air by approximately 8°C (12.4°F), which means that temperature output will depend on the ambient temperature inside the vehicle.
The climate module monitors seat heating through a NTC (negative temperature coefficient) temperature sensor. The temperature sensor is only used to monitor seat heating. Seat cooling is open loop, with no temperature signal provided back to the climate module. When a temperature selection is made through either of the rotary controllers, the ATC (automatic temperature control) module switchpack provides a medium speed CAN (controller area network) bus message to the climate module as a temperature value and attempts to heat or cool the seat accordingly.
The rotary control switch LED (light emitting diode)'s will illuminate if a selection is made when the ignition is in the on mode, but the Peltier cells will not operate until the engine is running. After the ignition is in the off mode, the climate module will retain the current temperature settings for approximately 15 minutes. After this period, the seats will be set to 'off' when the ignition is in the on mode.
Electric Rear Seats
The rear seat backrest can be adjusted for rake and also lumbar support using switch pack controls located in the rear door trim panel. The passenger side switch pack also contains an additional switch allow the rear seat occupant to move the front seat forward or backward to increase or decrease the rear leg room.
A motor and gearbox located in each of the rear seat backrest latches adjust the rake of the backrest in response to a request from the door switch pack. The switchpack receives a power supply from the CJB (central junction box). When a switch is operated the switch pack outputs a message on the LIN (local interconnect network) bus to the applicable front seat memory control module. The memory module then outputs the required power supplies to the seat motors to power them to the required position.
Each seat motor has four electrical connections; motor incline and recline, position sense and position sensor ground. The seat motor is operated using power supplies from the applicable front seat memory control module. The polarity of the power supplies is switched to provide the incline/recline functions. A position sensor sends signals back to the memory control module to prevent excessive seat movement.
The rear seats also have a lumbar adjustment in the backrest. This is a similar system to that used for the front seat. A 4-way switch lumbar control switch is located in the rear door switchpack and controls the operation of the backrest lumbar pump and valve block solenoids.