Electrically Adjustable Front Seat
General description of operation
The front seats of the car can be operated using a switch on the outside of each seat. Electric motors operate the seat length ways, elevate the seat cushion on the front or rear edge and also adjust the back rest inclination.
The seat has four electric motors with gears, that operate the functions.
Motors and gears for height adjustment and forward backward travel are fitted in the seat chassis, while the back rest inclination is filled in the seat frame.
The back rest inclination motor is connected by wires to two gears, the remaining motors are directly fitted to the gears.
Each motor has a thermostatic switch that protects against superheating. When the motor get hot the current is switched off for a few seconds until the motor cools.
To and including M93 all operation is carried out with the ignition key in the ON position.
From and including M94 a new operation has been introduced that also makes it possible to operate the seat when the ignition key is in the OFF position and the front doors are open.
The current M95 introduced a 10 pole connector, H10-27, that simplifies fault diagnosis regarding the motor voltage supply.
From and including M95 the passenger seat only has electrical operating without memory.
Description of operation -M93
When the ignition key is in the ON position the driver seat switches are supplied with voltage via fuse 25 and the passenger side switches via fuse 26.
By selecting a switch the corresponding motor is fed with voltage:
- The electric motor moving the seat forwards and backwards.
- The electric motor that raises or lowers the rear edge of the seat.
- The electric motor that raises or lowers the rear edge of the stool.
- The electric motor that changes the inclination of the seat backrest. The seat backrest can be folded down until it lays against the rear seat cushion. The forward movement is stopped by a microswitch.
Description of operation M94-
When the ignition key is in the ON position, voltage is supplied to the driver side switches via fuse 25 and the passenger side switches via fuse 26.
A relay, regulated by the door switches, makes it also possible to operate the seat when the ignition key is in the OFF position and the particular front door is open.
By selecting a switch the corresponding motor is fed with voltage:
- The electric motor moving the seat forwards and backwards.
- The electric motor that raises or lowers the rear edge of the seat.
- The electric motor that raises or lowers the rear edge of the stool.
- The electric motor that changes the inclination of the seat backrest. The seat backrest can be folded down until it lays against the rear seat cushion. The forward movement is stopped by a microswitch.