Buick Regal: Description and Operation

LUMBAR SUPPORT DESCRIPTION AND OPERATION (WITH MEMORY SEAT A44/A45)

The seat lumbar support system includes to following components:

• Seat lumbar support switch
• Seat bolster memory control module
• Seat memory control module
• Seat lumbar/bolster pump
• Air bladders

Seat Lumbar Switch

The driver seat lumbar support switch is a resistive ladder switch. The seat memory control module supplies the switch with a 5 V reference circuit. When a lumbar switch is pressed, the signal circuit from the seat memory control module is pulled low through the switch contacts and series of resistors indicating the lumbar support request. In response to this signal, the seat memory control module then commands the seat bolster memory module, via LIN serial data messages, to perform the required pneumatic lumbar movements.

Lumbar Operation

Once the seat memory control module receives a lumbar switch signal, the module will then command the seat bolster memory control module to perform the required pneumatic movements via LIN serial data messages.

The seat bolster memory control module contains the electronic circuitry for executing the commanded pneumatic seat adjustments, air direction solenoids and an output which supplies battery power to the external seat air pump motor when any of the air bladders require inflating.

Based on the LIN command from the seat memory control module, the seat bolster memory control module controls the appropriate air solenoids and activates or deactivates the external air pump in order to inflate or deflate the air bladders in the correct combination. When an air bladder needs inflating its solenoid opens and the pump motor is activated pumping air into the bladder. When an air bladder needs deflating its solenoid opens the release valve and air is allowed to bleed out of the bladder into the vehicle cabin.

LUMBAR SUPPORT DESCRIPTION AND OPERATION (WITHOUT MEMORY SEAT A44/A45)

The seat lumbar support system includes to following components:

• Seat lumbar support switch
• Seat lumbar support valve assembly
• Seat lumbar support pump
• Air bladders

The driver seat lumbar support switch is a resistive ladder switch. The seat lumbar support valve assembly supplies the seat lumbar support switch with a signal and low reference circuits. When a lumbar switch is pressed, the signal circuit from the seat lumbar support valve assembly is pulled low through the switch contacts and series of resistors indicating the lumbar support request. In response to this request, the lumbar adjuster valve assembly energizes its internal inflate solenoid and applies battery voltage through the lumbar support pump control circuit to the pump. The pump runs to inflate the appropriate support bladder until the switch is released.

MEMORY SEATS DESCRIPTION AND OPERATION

The memory seat system consists of the following components:

• K40 Seat memory control module
• S64 Seat adjuster switch
• S47 Seat memory switch
• M51 Seat horizontal motor
• M50 Seat front vertical motor
• M55 Seat rear vertical motor
• M56 Seat recline motor

S64D - S64D Seat Adjuster Switch - Driver
S47D - S47D Seat Memory Switch - Driver
K40 - K40 Seat Memory Control Module
M56D - M56D Seat Recline Motor - Driver
M51D - M51D Seat Horizontal Motor - Driver
M55D - M55D Seat Rear Vertical Motor - Driver
M50D - M50D Seat Front Vertical Motor - Driver

Driver Seat Adjuster Switch

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.

Seat Memory Control Module Power and Grounds

Battery voltage is supplied at all times to the seat memory control module through two different circuits.

One circuit is used by the module to apply power to the driver seat motors and lumbar motors, if equipped, when commanded ON. The second battery voltage circuit is used to power up module and supply a reference voltage to the seat position sensors. Ground is provided to the seat memory control module through a single 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.

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.

Auto Memory Recall and Easy Exit

The seat memory control module will not perform Auto Memory Seat Recall and Easy Exit functions unless these options are enabled in vehicle personalization using the radio/HVAC controls.

• Auto Memory Recall
• Easy Exit Options

The radio/HVAC controls reports the auto memory recall option settings to the seat memory control module via serial data message. The module will then store the memory recall option setting and examine it before making a memory seat adjustment. The auto memory recall option setting stored within the module will not change until the auto memory recall option setting in vehicle personalization is changed.

POWER SEATS SYSTEM DESCRIPTION AND OPERATION

The 8 - way power seat system consists of the following components:

• S64 Seat adjuster switch
• M51 Seat horizontal motor
• M50 Seat front vertical motor
• M55 Seat rear vertical motor
• M56 Seat recline motor

The 6 - way power seat system consists of the following components:

• S64 Seat adjuster switch
• M51 Seat horizontal motor
• M55 Seat rear vertical motor
• M56 Seat recline motor

Seat Motors

Each power seat motor contains an 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. The seat 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 driver 8 - way power seat, the rear vertical motor moves the rear of the seat cushion up or down, while the passenger 6 - way power seat, the rear vertical motor moves the entire seat up or down. The seat recline motor moves the angle of the seat back cushion forward or rearward.

Seat Operation

The seat adjuster switches provide both power and ground to the selected seat motors. When the switches are in an inactive state, the switch contacts are closed to the switch ground circuit All seat motors are reversible. For example, when the seat horizontal forward switch is pressed to move the entire seat forward, battery voltage is applied through the switch contacts and the seat horizontal motor forward control circuit to the motor. With the horizontal motor rearward switch contacts closed to the switch ground circuit, the motor runs in order 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 voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction. All seat motors are powered this way.

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