Electrically Adjustable Driver's Seat With Memory

��TElectrically Adjustable Driver's Seat With Memory:

WIRING DIAGRAM

Electrically Adjustable Driver Seat With Memory: Component Location:

COMPONENT LOCATIONS VIEW

Electrically Adjustable Driver Seat With Memory: Component ID:

COMPONENT ID
22A Main fuse board in the dashboard.
54 Door switches at bottom of door openings.
357
357A-D Electric motors, under the driver's seat.
357E-H Position sensors, electrically adjust- able seat with memory, under the seat on each motor shaft.
357J Memory switch unit on the outside of the seat.
357K Control module, electrically adjustable seat with memory.
445 16-pin data link connector under the dashboard adjacent to the steering column.
(H16-1)
446 Relay, electrically adjustable driver's seat, under the seat.
500 ICE control module
LHD: above main relay board in dashboard
RHD: behind main relay board in dashboard

8-Pin Connectors
H8-2 Under the left-hand seat.
H8-2 Under the right-hand seat.

33-Pin Connector
H33-3 Blue connector on connector bracket 'under the left-hand A pillar.

Grounding Points
G14 Grounding point, left-hand front seat member, under the seat.
G24 Grounding point, right-hand front seat member, under the seat.

DESCRIPTION OF OPERATION
The electrically adjustable front seat with memory consists of:
^ Two switches, one for manual seat adjustment and one for the memory.
^ Relay for adjustment of the driver's seat with a door open and/or the ignition switch in the Drive position,
^ Control module
^ Four electric motors with position sensors.

Switch Units
The switch units consist of a number of switches, one pole of which is supplied with battery voltage from pin 8 of the control module.

When a switch is activated, battery voltage will be supplied back to the corresponding switch input on the control module.

Relay
At the front of the driver's seat is a relay which enables the driver's seat to be adjusted when the driver 5 door is open and/or when the ignition switch is in the Drive position.

The ICE control module is grounded via pins 44 and 67 when any door is opened.

Pin 32 of the ICE control module in its turn grounds the operating coil of relay 446.

Control Module
Current (+30 circuit) is supplied to relay 446 via fuse 16. When the ICE control module grounds the relay with a door open or the ignition switch in the Drive position, this current is supplied to the control module which then supplies the motors, potentiometers and switches.

The control module continuously monitors the switches and when a valid combination of switches has been activated it performs the corresponding operation.

When any of the motors is running, the control module monitors the current consumption of the motors and the position of the seat via the position sensors (potentiometers).

The control module's memory can store three different seat settings and five diagnostic trouble codes. The memory retains the information even when the power supply has been switched off.

Motors
The motors are supplied with power via the control module.

The power supply is battery voltage and the polarity changes according to the direction of rotation.

Position Sensors
The position sensors consist of potentiometers, one on each motor shaft.

Pins 1 and 3 of the potentiometers are supplied with about 5 V from the control module. When the motor shaft rotates, the voltage on the centre tap of the potentiometer (pin 2) changes between 0.4 V and 4.6 V. By measuring this voltage, the control module can determine the position of the seat.

Manual Seat Adjustment
Only two motors can be run at the same time. If more than two motors are activated simultaneously, all the motors will stop.

Fore-and-aft adjustment of the seat and inclination of the seat cushion are limited by mechanical stops. The control module supplies the motors with current only as long as the corresponding switch in the manual control is activated (although no longer than one minute).

The backrest has no mechanical stop to limit its rake in either direction.

Using The Memory
^ Adjust the seat to the desired position by means of manual adjustment switch 357.
^ Press memory store button 357J and keep it depressed.
^ Press any of the memory buttons marked 1-3 briefly (the control module will now read all seat positions and store the settings in its memory).
^ Release the button marked M.

If any of the position sensors is defective, no new seat setting will be stored in the memory. The earlier setting will be retained.
^ When using the memory to reset the seat, press any of the memory buttons (1-3) and keep it depressed.

The control module will then read all the position sensors and run the motors until the seat setting corresponds to the setting stored in the memory, or until the memory button is released.

FAULT DIAGNOSIS HINTS
Faults detected by the control module are stored in the memory as diagnostic trouble codes. These trouble codes can be read by means of an ISAT Scan Tool.

If the control module detects a fault in any of the components, or if a motor runs too slowly, the component or motor will be stopped.

The ISAT scan tool can also be used for obtaining readouts of each individual switch and the settings of the position sensors.