This document discusses electromechanical seat adjustment systems. It describes the components of power seat systems including seat controls, motors, drive systems, and position sensors. Various types of power seat adjustments are defined including 2-way, 4-way, 6-way and 8-way systems. Additional seat features like climate control, lumbar support, memory positions and adaptive seats are also summarized. Troubleshooting tips for power seat issues are provided.

1. MAT 1133: Comfort and Safety Technology
Chapter 1:
Electromechanical Seat Adjustment
System

2. •Power seat allow the driver or passengers to adjust the
seat to the most comfortable position.
•The major component of the system are the seat control
and the motor.

3. Power seat systems
1. Two-way : seat adjust forward and backward.
2. Four-way : Seat adjust forward/ backward, and up/ down
3. Six-way : Seat adjustment moves the seat forward/backward,
up/down, and front and rear tilt (recline seatback).
4. Eight-way: Seat adjustment moves the seat forward/backward,
up/down, front and rear tilt (recline seatback) &
upward/downward tilt (cushion)

4. 8-way-seat adjustment

5. Power Seat Components
1. Seat control switch
2. Motor
3. Drive system (screw drive, rack and pinion drive or
transmission drive)
4. Seat track (many seat track systems contain the motor and
drive system)
5. Seat position sensors for memory systems (potentiometers)
6. Control module
7. Relays
8. Fuse or circuit breaker

8. • Power seat movement is controlled by using one or a combination of reversible motors.
• Reversing the direction of the switch will reverse the polarity of the current to the
motor, causing the motor to turn in the opposite direction and reversing the direction of
the seat.
• Typically, two motors are used four-way systems while three are used on a six-way
systems.
• A trimotor uses three motors grouped together as an assembly.
• The motors in the seat assembly turn a screw drive, rack and pinion drive or gear
transmission drive to alter seat position.
• Multiple motor power seat systems use integrating gears to move the seats in a variety
of directions.
• The rack and pinion or worm gear drive transmission is used with a single motor system.

10. RACK AND PINION WORM GEAR

12. Functional wiring diagram

13. • Some seat adjustment systems operate by using a separate motor for each
position movement. These motors may be controlled by:
 three separate switches.
 one switch with multiple functions
• Some seat adjustment systems may not be able to perform more than one
function, such as up and back, at the same time.

14. Types of seats
• Climate-Controlled Seats
• Power Lumbar Supports
• Memory Seats
• Adaptive Seats

15. Climate-Controlled Seats
 Climate-controlled seats have a seat
control unit under the seat.
 A thermoelectric device not only
heats but cools the seat.
 A blower motor beneath the seat
cushion pushes heated or cooled air
through perforations in the leather
seat, producing a light feeling or air
movement.
 The heating and cooling operation of
a climate-controlled seat is made
possible by the Peltier effect.

16. Power Lumbar Supports
 Power lumbar supports are
a feature of some seats,
usually on the driver side.
 The lumbar area describes
the lower area of the back.
 A bladder in the lower seat
back is inflated or deflated
according to the desires of
the person in the seat.

17. Memory Seats
 Typically, switches allow
programming for at least two
driver’s seat position.
 The module is programmed by
putting the seat in the position
desired.
 Then a button is depressed and
held to enter the position into
memory.

18. Storing seat position
• Switch on ignition.
• Set the desired seat positions.
• Keep memory button M depressed and also press person button 1, 2 or 3 until an
audible signal confirms that the position has been stored. The individual setting is
now stored under the desired person button.

19. Adaptive Seats
• Adaptive seats use memory seat positions but move the
adjustment to fit the driver as she or he shifts in the seat.

20. *Storing seat position
• Press the switch in the direction indicated by the arrow until the desired setting is reached.
• A - Seat height adjustment
B - Fore-and-aft position adjustment
C - Seat angle adjustment
D - Backrest angle adjustment
E - Lumbar support (pelvis and spinal column support)
• To permit a relaxed sitting posture, the backrest curvature is continuously adjustable in
vertical and horizontal directions for individual pelvis and spinal column support.
• Press the switch in the direction indicated by the arrow until the desired backrest curvature is
reached.
• F - Adjusting the backrest side bolsters (adaptive sports seat only)
*Porsche model

21. Troubleshooting
 When troubleshooting electric seats, use common sense.
 If only the up and down positioning has failed, check that motor and circuit first.
 If both seats are not working, look to the power source (Power is supplied to the
seat all times).
 The most common problems with power seats are with switches and motors.
 If the seats do not operate, first check the fuse or circuit breaker.
 Most vehicles use circuit breakers due to the possibility of something physically
becoming lodged between seat and floor.

22.  Sometimes the relay clicks when the switch is activated but
the seat does not move. In this case, the breaker is operating
but the relay or motor could be defective.
 A test light should light up on both sides of the circuit
breaker, which is usually located on the fuse panel. Remove
the seat control and check for voltage and ground
connections.