Circuit/System Description
The memory seat module (MSM) monitors the current supplied to the seat adjuster motors. The MSM can detect both absolute and differential current levels from the seat motors. Absolute current is the maximum allowable current the module will supply to the motors. A differential current mismatch occurs when the current supplied to the seat motors does not match the current returning from the motors.
The memory seat module (MSM) monitors the current supplied to both steering column motors. The MSM can detect both absolute and differential current levels from the these motors. Absolute current is the maximum allowable current the module will supply to the motors. A differential current mismatch occurs when the current supplied to the motors does not match the current returning from the motors.
The memory seat module (MSM) supplies a 5-volt reference voltage to the driver seat and tilt/telescoping steering column position sensors. The MSM monitors this reference voltage to ensure the accuracy of the voltages being returned from the sensors. If the voltage exceeds the normal operating range, errors will occur in the memory recall operations of the seat and tilt/telescopic steering.
The memory seat module (MSM) controls the seat and steering column motors via half bridges that are divided into 2 groups that are connected to separate power rails internal to the module. When a power seat switch is pressed or when a memory recall is requested, each seat and steering column motor receives battery voltage and ground from the MSM via the motor control circuits. All motors are reversible, so the direction the motor rotates depends on which control circuit voltage is applied and which control circuit ground is applied. When the switch is operated in the opposite direction, the module reverses the polarity and applies voltage and ground to the opposite circuits to move the seat or steering column in the opposite direction.
Power seat lumbar support is completely controlled through the seat lumbar adjuster switch. Battery voltage is supplied at all times to the seat lumbar adjuster switches through a 25 A circuit breakers located in the I/P fuse block. When the lumbar switches are in an inactive state, the switch contacts are closed to the switch ground circuit.
The lumbar horizontal motor is reversible. For example, when the lumbar horizontal forward switch is pressed to move the lumbar support forward, battery voltage is applied through the switch contacts and the lumbar motor forward control circuit to the motor. The motor is grounded through the lumbar motor rearward switch contacts and the lumbar motor rearward control circuit to the motor. The motor runs in order to drive the lumbar support forward toward the occupants back until the switch is released. Moving the lumbar support rearward works similarly to moving the lumbar support forward, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction.
Reference voltage is supplied to the memory seat adjuster switch from the driver door lock/window switch. When a memory switch is pressed, reference voltage is applied through the switch contacts, a series of resistors and thorough the memory switch signal circuit to the door lock/window switch. The door lock/window switch then sends a serial data message to the memory seat module (MSM) indicating the memory recall request. The MSM then commands the appropriate seat motors to move to the pre-recorded seat positions stored in memory in response to the switch input.
Battery positive voltage is supplied at all times to the memory seat module (MSM) through the 10 A MSM fuse located in the I/P fuse block. This voltage is used by the MSM for logic power and to supply battery reference voltage to the seat adjuster switch. Battery positive voltage is also supplied at all times to the MSM through the 25 A LT/PWR/SEAT circuit breaker. This voltage is connected to a power rail internal to the MSM and is used to drive the power seat motors and seat heater elements on vehicles equipped with heated seats. Each seat adjuster motor is controlled by the MSM through 2 motor control circuits. The MSM connects all motor control circuits 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 MSM checks to see if the reference voltage is shorted to ground or battery before enabling any of the seat motors.
All motors are reversible. For example, when the seat switch is operated to move the entire seat forward, battery positive voltage is applied through the switch contacts and the power seat horizontal forward switch signal circuit to the MSM. In response to this signal, the MSM 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 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.
Power seat without memory is completely controlled through the seat adjuster switch. Battery voltage is supplied at all times to the seat adjuster switches from the LT/PWR/SEAT circuit breaker and the RT/PWR/SEAT circuit breaker that are located in the I/P fuse block. When the seat adjuster 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. The motor is grounded through the horizontal motor rearward switch contacts and the horizontal motor rearward control circuit to the motor. 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 positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction. All seat motors are powered this way.
Memory Seats Description and Operation
The memory seat system consists of the following components
- Memory seat module
- Driver door lock/window switch
- Driver seat adjuster switch
- Driver memory seat adjuster 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
Power Seats System Description and Operation
The driver power seat system may consist of the following components
- Seat Adjuster Switch
- Seat Horizontal Motor
- Seat Front Vertical Motor
- Seat Rear Vertical Motor
- Seat Recline Motor
- LT/PWR/SEAT Circuit Breaker 25 A
The front passenger power seat system may consist of the following components
- Seat Adjuster Switch
- Seat Horizontal Motor
- Seat Recline Motor
- RT/PWR/SEAT Circuit Breaker 25 A