Memory Seats Description and Operation
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Memory Seats Description and Operation
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Memory Seat System Components
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The memory seat system consists of the following components:
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Seat memory control module
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Driver Seat Memory Switch
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Seat horizontal motor/sensor
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Seat front vertical motor/sensor
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Seat rear vertical motor/sensor
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Seat back recline motor/sensor
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Driver Seat Personalization Option
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The seat memory unit does not perform the "remote memory retrieval" and "driver seat easy exit/entry" functions if these personalizations have not been activated in the audio system. See Personalization of the Vehicle in the Owner's Manual. The audio system reports the vehicle personalization option settings to the seat memory control module as well as other receiving modules via GMLAN message each time the ignition switch is cycled to the ON position. The seat memory control module will then store the seat personalization option settings and examine them before making a memory seat adjustment. The seat personalization option settings stored within the seat memory control module will not change until the memory recall option setting in the audio system is changed and the ignition switch is cycled to the ON position.
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Driver Seat Adjuster Switch
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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 seat 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 driver seat to move in response to the switch signals.
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 seat back 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 or rearward.
The seat memory control module controls all seat motors via half bridges that are connected to a single power rail internal to the module. The module connects all motor outputs on the power rail to a common reference point whenever they are not in operation. This reference point is biased to approximately 2.5 V. The seat memory control module checks to see if this reference voltage is shorted to ground or battery before enabling any seat motor. All 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.
All seat motors are reversible. For example, when the seat switch is pressed to move the entire seat forward, ground is applied through the switch contacts and seat horizontal forward switch signal circuit to the seat memory control module. In response to this signal, the seat memory control 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 opposite circuits causing the motor to run in the opposite direction. All seat motors are powered this way.
The seat motors are equipped with 2 wire hall effect type position sensors internal to the motor. The sensors are monitored by the seat memory control module and are used to determine seat positions when storing or recalling memory settings. The seat memory control module supplies the sensors with a common 12 V reference circuit and separate signal circuits. During seat motor operation, the hall effect position sensor provides a determined number of pulse signals for every revolution of the motor shaft. These pulse signals (Counts) range from 0 - 65,535. High scan tool count values indicate forward or upward seat positions while low count values indicate rearward or downward seat positions.
Memory recalls via the memory switch require the driver to press and hold the memory button until the seat reaches it's memory position.
Ground from the seat memory control module is supplied at all times through the 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 rearview mirrors (also adjustable pedals and power tilt/telescoping steering column if equipped). One method is to save and retrieve the memory positions by using the memory buttons. The other method is to use the key fob.
Unique memory positions may be saved for up to 5 drivers. Two unique memory positions can be saved via memory recall switches 1 and 2. To save memory positions for driver 1:
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Adjust the driver seat and the exterior mirrors (also adjustable pedals and power column if equipped) to the desired position.
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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.
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A second seating position for driver 2 may be programmed by repeating the above steps and pressing memory button 2. There is no correlation between fob 1 and memory button 1 or fob 2 and memory button 2. The positions stored for each of the memory recall buttons can be recalled by pressing and holding the memory recall button until the memory controlled devices reach their saved position.
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 will share the same set of saved positions but will be unique from key fob IDs 1 and 2.
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Note
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The key fob memory recall positions are not tied to the positions stored to the memory seat recall switches.
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Key fobs 1, 2 and 3 (up to 3 unique sets of positions) can be saved by:
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Press Unlock on the desired key fob
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Place the ignition in the ON position
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Adjust seat and mirrors to desired positions
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Keyless Entry and Memory Recall Personalization
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When a keyless entry transmitter is used in order to unlock the vehicle's doors, the body control module communicates the unlock command and which driver performed the command to the seat memory control module via a serial data message. Vehicle lock/unlock functions and memory recall settings may be personalized. For functional descriptions and personalization instructions, refer to the vehicle owners manual.
