General Description

The control module located under the seat cushion operates four different motors in all. Three of the motors are located under the seat, the fourth is located in the backrest.

The control module with memory receives information on the seat position from signals from four position sensors. These are potentiometers driven by a worm gear on the output shaft of each motor.

The control module has a microprocessor and a number of relay functions, a dual relay for each motor and a main relay for the main power supply.

Seat positions are stored in an EEPROM type memory. This type of memory stores information indefinitely, even if there is no power to the control module.


NOTE: When replacing the control module with a new module always check that the new control module has P/N 9174902 (left seat) or 9174903 (right seat). The earlier type of control module has a different type of diagnostics. The older versions operate correctly with the different seat functions, but their diagnostic system cannot communicate with the Volvo Scan Tool (ST).