Memory Seats

Memory Seats Description and Operation

The memory seat system consists of the following components:

* Seat memory control module

* Driver seat adjuster switch

* Driver seat memory switch

* Driver seat horizontal motor

* Driver seat front vertical motor

* Driver seat rear vertical motor

* Driver seat recline motor

* Driver seat horizontal motor position sensor

* Driver seat front vertical motor position sensor

* Driver seat rear vertical motor position sensor

* Driver seat recline motor position sensor

Driver Seat Adjuster Switch

Ground is supplied at all times to the driver seat adjuster switch through the switch ground circuit and G305. The seat memory control module supplies a low current voltage to each signal circuit of the seat adjuster switch. When the driver seat adjuster switches are pressed, the appropriate signal circuit from the seat memory control module is pulled low through the switch contacts indicating the power seat command. The seat memory control module then commands the appropriate driver seat motor to move in response to the switch signal.

Memory Recall Option

The seat memory control module cannot perform Automatic Memory Seat Recall and Easy Exit functions unless these options are activated in the driver information center (DIC), refer to the Owner's Manual. The DIC reports the memory recall option setting to the seat memory control module as well as other receiving modules via serial data message. The module will then store the memory recall option setting and examine it before making a memory seat adjustment. The memory recall option setting stored within the module will not change until the memory recall option setting in the DIC is changed.

Seat Memory Control Module Power and Grounds

Battery positive voltage is supplied at all times to the seat memory control module through a 25 A circuit breaker located in the instrument panel fuse block. This voltage is used by the module to apply power to the driver seat and lumbar motors when commanded ON. Battery positive voltage is also applied at all times to the seat memory control module through a 5 A fuse located in the underhood fuse block. This voltage is used to power up module, supply voltage to the seat and lumbar adjuster switches, seat position sensors and the seat haptic motors. Ground is provided to the seat memory control module through the module ground circuit and ground connection.

Seat Motors

There are 4 motors that move the position of the seat. These are the seat horizontal motor, seat front vertical motor, seat rear vertical motor, and the seat back recline motor. The horizontal motor moves the entire seat forward and rearward. The seat front vertical motor moves the front of the seat cushion up or down. The seat rear vertical motor moves the rear of the seat cushion up and down. Due to the seat adjuster switch design the front tilt and the seat height adjuster motor cannot be operated at the same time The recline motor moves the angle of the seat back forward or rearward.

The seat memory control module controls all seat and lumbar motors via half bridges that are connected to a single power rail internal to the module. The module connects all seat and lumbar motor outputs to a common ground whenever they are not in operation. The seat memory control module checks to see if any motor control circuits are shorted to ground or voltage before enabling any seat or lumbar motor. All of the 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.

All seat motors are reversible. For example, when a seat switch is pressed to move the entire seat forward, ground is applied through the switch contacts onto the seat horizontal forward switch signal circuit to the seat memory control module. In response to this signal, the module applies battery voltage through the driver seat horizontal motor forward control circuit and ground through the driver seat horizontal motor rearward control circuit to the motor. The motor runs in order to drive the entire seat forward. Moving the entire seat rearward works similarly to moving the entire seat forward, except that battery voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction. All of the motors are powered this way.

Position Sensors

To monitor seat position, each seat motor has an internal 2-wire hall-effect position sensor. The seat memory control module supplies all the sensors with a common 12 V reference when the seat is moving and a unique signal circuit for each sensor. During seat motor operation, the position sensors provide a specific number of pulse signals for every revolution of the motor shaft.

The seat memory control module determines seat position by keeping a running counter where movement in the forward/upward direction adds counts and movement in the rearward/down direction subtracts counts. The value of the counter will be in the range of 0 - 65,535

The value of these counters, which represent seat positions, are stored in memory for future seat memory recall operation. During a memory seat position recall, the seat memory control module moves the seat in such a way to return it the stored counter value.

Memory Functions

In all power modes except crank, memory recalls can be initiated by pressing and holding one of the memory position buttons until the seat reaches the stored memory position associated with the activated button. This is called a supervised recall.

Un-supervised recalls, a momentary push of memory recall switch, are available when the ignition is ON and the vehicle transmission is the park position.

The seat memory control module supplies a ground at all times through a low reference circuit to the driver seat memory switch. The module also supplies memory set and memory recall signal circuits to the seat memory switch. When a memory recall switch is pressed, the signal circuit from the seat memory control module is pulled low through the switch contacts and a series of resistors indicating the memory recall request. In response to this signal, the seat memory control module commands the appropriate seat motors to move to the pre-recorded seat positions stored in memory.

There are two methods to save and recall memory positions for the driver seat and outside rear view mirrors (also adjustable pedals and power tilt/telescoping steering column if equipped). The first method to save and recall memory positions is by using the memory set buttons, the second method is by using the key fob.

Up to six unique memory positions may be saved. Two preferred memory positions can be saved via memory recall switches 1 and 2. In addition an exit position may be saved via the memory exit switch.

To save memory positions for driver 1:

* Adjust the driver seat and the exterior mirrors (also adjustable pedals and power column if equipped) to the desired position.

* Simultaneously press and hold the memory recall switch MEM button and button 1 until a signal chime sounds indicating the memory position is saved for driver 1.

A second seating position for driver 2 may be programmed by repeating the above steps and pressing memory button 2.

A single EXIT position may be programmed by repeating the above steps and pressing memory exit button.

In addition to the two memory recall switch positions, three remote memory recall positions for Drivers 1, 2, and 3 may be saved. Drivers 1 and 2 will each have a unique set of remote memory recall positions saved for key fob ID's 1 and 2. A third unique set of positions for Driver 3 may also be saved for all additional key fobs 3 through 8. Key fob ID's 3 through 8 will be recognized by the Seat Memory Control Module as key fob ID 3. Key fob ID 3 through 8 will share the same set of saved positions but will be unique from key fob IDs 1 and 2.

Note: The key fob memory recall positions are not tied to the positions stored to the memory seat recall switches.

Key fobs 1, 2 and 3 (up to 3 unique sets of positions) can be saved by:

* Unlock the vehicle with the desired key fob

* Place the ignition in the ON position

* Adjust seat and mirrors to desired positions

* Turn the ignition OFF

Easy Exit

If the EASY EXIT SEAT function is activated in the DIC as mentioned above, the vehicle is in the OFF power mode, and the seat memory control module sees the driver door is ajar, the driver seat will automatically move to the saved memory exit position.

Recall Personalization

Refer to the owners manual for the following memory personalization options:

* Auto recall when the door is opened.

* Auto recall with key ON

* Easy exit