Memory Seats
MEMORY SEATS DESCRIPTION AND OPERATIONThe memory seat system consists of the following components:
- Seat Adjuster Switch
- Memory Seat Module (MSM)
- Seat Horizontal Motor
- Seat Front Vertical Motor
- Seat Rear Vertical Motor
- Seat Recline Motor
- Seat Horizontal Position Sensor
- Seat Front Vertical Position Sensor
- Seat Rear Vertical Position Sensor
- Seat Recline Position Sensor
- Memory Function Switch
- Driver Door Switch Assembly (DDSA)
- Driver Door Module (DDM)
- SEATS Circuit Breaker 30 A
- SEATS Fuse 10 A
Personalization - Driver Information Center (DIC)
Personalization in the Setup menu of the driver information center (DIC) must be in the active state for memory seats to operate. A check mark appearing after the word Personalization on the display screen indicates that the feature is active. For more detailed information concerning programming of Personalization and other memory recall features controlled through the DIC, refer to Driver Personalization in Personalization
Personalization Option - Dash Integration Module (DIM)
The memory seat module cannot perform memory recall functions unless the Personalization Option is activated. The personalization option is located in the 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 SEATS Fuse located in the left 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 memory seat module through the battery positive voltage circuit from the SEATS Circuit Breaker located in the left rear fuse block. This voltage is used to power up MSM and also to apply power to the seat motors when commanded. Battery positive voltage is also supplied to the MSM from the SEATS Fuse that also supplies voltage to the seat adjuster switch. The MSM monitors this voltage circuit in order to determine if battery voltage is supplied to the seat adjuster switch. The MSM is grounded through the module ground circuit and G307.
Seat Motors
The MSM controls the movement of each of the above mentioned seat directional motors. All of the seat motors operate independently of each other. Each motor contains a electronic circuit breaker (PTC), that opens in the event of a circuit overload and will reset only after voltage has been removed from the circuit.
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. The seat vertical motors may operate independently to tilt the front or rear of the seat cushion up or down. Both vertical motors can also run simultaneously to move the entire seat up or down. The recline motor moves the angle of the seat back forward or rearward.
All motors are reversible. For example, when the seat switch is operated to moved the entire seat forward, battery positive voltage is applied through the horizontal forward 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 MSM supplies ground to the motor through the driver seat horizontal motor rearward control circuit. 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 it's 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 DDSA is momentarily grounded. In response to this signal, the DDSA then sends a message via the simple bus interface to the DDM indicating that a memory function signal has been received. The DDM then sends the message to the MSM via class 2 serial data line.
The current seat position may be recorded for 2 different drivers. To record a position, adjust the drivers seat 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 all four seat 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 all four seat position sensors for the appropriate driver.
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 run the seat 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 run 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 transmitter sends a signal to the diversity antenna module. The module interprets the signal, then communicates the unlock command and which driver performed the command via a class 2 message over the serial data line to the appropriate modules and the MSM. The MSM will then recall any previously programed personalization easy exit or memory seat positions. For more information concerning the programing of the personalization feature refer to Driver Personalization in Personalization.
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.