The memory seat system consists of the following components:
• | Memory Seat Module (MSM) |
• | Seat Horizontal Motor |
• | Seat Front Vertical Motor |
• | Seat Rear Vertical Motor |
• | Lumbar Horizontal Motor |
• | Lumbar Vertical Motor |
• | Seat Horizontal Position Sensor |
• | Seat Front Vertical Position Sensor |
• | Seat Rear Vertical Position Sensor |
• | Seat Recline Position Sensor |
• | Lumbar Horizontal Positional Sensor |
• | Lumbar Vertical Position Sensor |
• | Memory Function Switch |
• | Power Seat Circuit Breaker 30 A |
Personalization Option
The memory seat module (MSM) cannot perform memory recall functions unless the
Personalization Option is activated. The personalization option is located in the
dash integration module (DIM). The DIM reports the personalization option setting
to the MSM, as well as other receiving modules, via a class 2 message each
time the ignition switch is cycled to the ON position. The MSM will then store the
personalization option setting and examine it before making a memory seat adjustment.
The personalization option setting stored within the MSM will not change until the
personalization option setting in the DIM is changed and the ignition switch is cycled
to the ON position.
Seat Adjuster Switch
Battery positive voltage is supplied at all times to the seat adjuster switch
from the MEM Fuse located in the rear fuse block. When the seat switches are pressed
they send a 12-volt signal to the MSM. The MSM commands the selected seat motors to
move in response to the switch signal.
MSM Power and Ground
Battery positive voltage is supplied at all times to the MSM through the battery
positive voltage circuit from the PWR SEAT Circuit Breaker located in the rear fuse
block. This voltage is used to power up MSM and also to apply power to the seat motors
when commanded. The MSM is grounded through the module ground circuit and G 301.
Seat Motors
The MSM controls the movement of each of the above mentioned seat directional
motors and the 2 lumbar motors. Refer to
Lumbar Support Description and Operation
. All of the seat motors operate independently
of each other. Each motor contains a electronic circuit breaker (PTC), which will
reset only after voltage has been removed from the motor.
There are 4 motors that move the position of the seat. These are the
seat horizontal motor, front vertical motor, rear vertical motor, and the recline
motor. The horizontal motor moves the entire seat forward and rearward. Both vertical
motors run simultaneously when the seat switch is operated in order to move the entire
seat up and down. Or they can be selected independently to vertically tilt the front
or rear of the seat up and down. The recline motor moves the angle of the seat back
forward and rearward.
All motors are reversible. For example, when the seat adjuster switch is operated
to moved the entire seat forward, battery positive voltage is applied through the
entire seat switch contacts and the power seat horizontal forward switch signal circuit
to the MSM. In response to this signal, the MSM applies battery positive voltage through
the driver seat horizontal motor forward control circuit to the horizontal motor.
The motor is grounded through the driver seat horizontal motor rearward control circuit
to the motor. The motor runs to drive the entire seat forward until the switch is
released. Moving the entire seat rearward works similarly to moving the entire seat
forward, except that battery positive voltage and ground are applied on the opposite
circuits causing the motor to run in the opposite direction. All other seat motors
are also powered this way.
The MSM provides each seat motor with a soft stop. The module will actually
stop the motor just before the physical end-of-travel for that motor. This decreases
the stress on each motor. If a motor reaches the end-of-travel due a soft stop and
the seat switch is released and then activated again, the seat will move a short distance
farther to the physical travel limit.
Position Sensors
The seat position sensors are potentiometers which are either attached directly
to the motor's transmission cable or are an internal part of the motor. The MSM supplies
a 5-volt reference voltage through the 5-volt reference circuit and ground through
the low reference circuit to the respective seat position sensors. When the motor
or cable rotates, the resistance of the potentiometer varies changing the feedback
voltage of the position sensor signal circuit. This voltage varies from 0.25 volts
to 4.75 volts. The MSM monitors this voltage signal to determine the position
of the seat.
When a memory set command is received, the MSM records the seat position by
storing the feedback voltage from each position sensor. Then, when a memory recall
command is received, the MSM moves the motors until the position sensor feedback voltages
equals the feedback voltages stored in memory.
Memory Functions
When a memory function switch is pressed, the associated signal circuit of the
driver's door switch assembly (DDSA) is momentarily grounded. In response to this
signal, the DDSA then sends a message via the simple bus interface to the driver door
module (DDM) indicating that a memory function signal has been received. The DDM then
sends the message to the MSM via the class 2 serial data line.
The current seat position may be recorded for 2 different drivers. To
record a position, adjust the drivers seat including the lumbar support to a comfortable
position, then press and hold button 1 for 5 seconds, a double beep
will sound each time a memory position is set. A second seat position may be programmed
by repeating the above steps and pressing button 2. When the MSM receives a
memory set message, the MSM records the feedback voltages from the position sensors
for the appropriate driver. The easy exit position is programmed by moving the seat
to the desired exit position and then holding the exit button for 5 seconds.
Two easy exit positions can be programmed, one for each driver. When the MSM receives
a set exit message, the MSM records the feedback voltages from the four seat position
sensors for the appropriate driver. The lumbar support is not involved in the easy
exit function.
When the memory recall 1 or 2 button is pressed, a single chime
is sounded through the radio in order to acknowledge the signal and the MSM receives
the memory recall message. In response to this message, the MSM applies battery positive
voltage to the motors until the position sensor feedback voltages equal the feedback
voltages stored in memory for the appropriate driver. When the EXIT button is pressed,
a single chime is sounded in order to acknowledge the signal and the MSM receives
the easy exit message. In response to this message, the MSM applies battery positive
voltage to the seat motors until the position sensor feedback voltages equal the feedback
voltages stored in memory for the appropriate driver.
Memory recall will not work if the shift lever is out of NEUTRAL (N) or PARK
(P).
Recall Personalization
When a keyless entry transmitter is used in order to unlock the vehicle doors,
the remote keyless entry (RKE) module communicates the unlock command and which driver
performed the command to the MSM via a class 2 message. There are
2 personalized recall options when the MSM receives an unlock message:
• | Recall immediately upon receipt of the RKE message. |
• | Do not recall upon receipt of an RKE message. Recall functions are only
performed with the memory buttons. |
Memory Inhibit/Enable
The memory seat module receives the ignition switch signal and the gear selector
position via class 2 messages. When the ignition switch is in the OFF position,
memory record, memory recall, personalization recall, and exit recall functions are
all allowed. When the ignition switch is in the ON position and the gear selector
is in the PARK position, only the recall personalization function is deactivated and
all other memory functions are allowed. When the ignition switch is in the ON position
and the gear selector is out of the PARK position, only memory record is allowed,
all other memory seat functions are not allowed.