Lumbar Support Description and Operation Without Memory A45

The front and rear passenger seat lumbar support systems consist of the following components:

The lumbar switch provides both power and ground to the selected lumbar motors. Battery positive voltage is supplied at all times to the front passenger seat lumbar switch from the MSM/RT FRT PWR SEAT Circuit Breaker located in the rear fuse block. Battery positive voltage is supplied to both rear seat lumbar switch from the RR SEAT LUM fuse also located in the rear fuse block. Ground for the front and rear lumbar switches is supplied from the following ground stakes:

The lumbar support system consists of two lumbar motors, horizontal and vertical, that operate independently of each other. Each motor contains an electronic circuit breaker (PTC) that will reset only after voltage has been removed from the motor. The lumbar horizontal motor moves the lumbar support forward and rearward and the lumbar vertical motor moves the lumbar support up and down.

When the lumbar switch is operated to move the lumbar support rearward, battery positive voltage is applied through the lumbar rearward switch contacts and the lumbar motor rearward control circuit to the lumbar horizontal motor. The motor is grounded through the lumbar forward switch contacts and the lumbar motor forward control circuit to the horizontal motor. The motor runs to drive the lumbar support rearward away from the occupant's back until the switch is released. Moving the lumbar support forward works similarly to moving the lumbar support rearward, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction.

When the lumbar switch is operated to move the lumbar support up, battery positive voltage is applied through the lumbar up switch contacts and the lumbar motor up control circuit to the lumbar vertical motor. The motor is grounded through the lumbar down switch contacts and the lumbar motor down control circuit to the vertical motor. The motor runs to drive the lumbar support up until the switch is released. Moving the lumbar support down works similarly to moving the lumbar support up, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction.

Lumbar Support Description and Operation With Massaging Lumbar AM3

The massaging lumbar system consists of the following components:

With the ignition in the ON position, battery positive voltage is supplied to the driver and front passenger lumbar massage switches from the memory seat module (MSM). When the switch is momentarily pressed to initiate massage operation, battery voltage is applied through the switch contacts and the lumbar massage switch signal circuit to the MSM. In response to this signal, the MSM then cycles battery positive voltage and ground through the lumbar motor up and down control circuits to the lumbar vertical motor. The motor will then continuously move the lumbar support 50 mm in both the up and down directions for 10 minutes or until the lumbar switch is momentarily pressed to cancel the operation. When massage operation has ceased, the MSM will return the lumbar support to the position from which massage was initiated.

During massage operation, the lumbar horizontal support can be adjusted without interruptions to the massage cycle by operating the lumbar switch in either the forward or rearward directions. However, manually moving the lumbar vertical switch in either the up or down directions will cancel the massage operation and move the lumbar support in the desired direction.

The lumbar vertical motor is reversible. When commanded, it will move the lumbar support in the up and down directions. To protect itself, the 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 lumbar vertical motor is controlled by the memory seat module during manual movement and massage operation.

The lumbar vertical position sensor is a potentiometer, which is attached directly to the lumbar vertical motor. The memory seat module (MSM) supplies a 5 volt reference voltage through the 5 volt reference circuit and ground through the low reference circuit to the sensor. When the motor rotates, the resistance of the potentiometer varies, changing the feed back voltage of the sensor signal to the MSM. This voltage varies from 0.25 volts to 4.75 volts. The MSM monitors this voltage to determine the vertical position of the lumbar support. When the massage function is turned OFF or canceled, the MSM will stop massage movement at the original starting position.

Lumbar Support Description and Operation With Memory A45

The driver seat lumbar support system with memory (A45) consists of the following components:

The MSM is referenced in the Tech 2 as the driver position module (DPM).

Battery positive voltage is supplied at all times to the driver and front passenger seat lumbar switches from the MSM LOGIC/RF MASSAGE Fuse located in the rear fuse block. When the lumbar switches are pressed they send a 12-volt signal to the memory seat module (MSM). The MSM then commands the lumbar motors to move in response to the switch signals.

The lumbar support system consists of 2 motors, horizontal and vertical, that operate independently of each other. The lumbar horizontal motor moves the lumbar support in the forward or rearward directions while the lumbar vertical motor moves the lumbar support in the up or down directions. Each 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.

Soft stop functions are not used for driver seat motors that are controlled by either a memory or non-memory MSM. However, soft stop functions are used for the MSM controlled steering column motors. Refer to Steering Wheel and Column Description and Operation.

When the lumbar switch is operated to move the lumbar support forward, battery positive voltage is applied through the switch contacts and the driver seat lumbar forward switch signal circuit to the memory seat module (MSM). In response to this signal, the MSM applies battery positive voltage through the lumbar motor forward control circuit and ground through the lumbar motor rearward control circuit to the motor. The motor runs to drive the lumbar support forward toward the occupant's 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 the opposite circuits causing the motor to run in the opposite direction. The MSM also controls the lumbar horizontal motor during memory recall functions.

For front passenger lumbar horizontal movement refer to Lumbar Support Description and Operation without memory-A45.

When the lumbar switch is operated to move the lumbar support up, battery positive voltage is applied through the switch contacts and the lumbar up switch signal circuit to the memory seat module (MSM). In response to this signal, the MSM applies battery positive voltage through the lumbar motor up control circuit and ground through the lumbar motor down control circuit to the motor. The motor runs to drive the lumbar support up until the switch is released. Moving the lumbar support down works similarly to moving the lumbar support up, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction. The MSM also controls the lumbar vertical motor during memory recall functions.

The lumbar position sensors are potentiometers which are an internal part of each lumbar motor. The memory seat module (MSM) supplies a 5-volt reference voltage through the 5-volt reference circuit and ground through the low reference circuit to each lumbar position sensor. When the lumbar motor rotates, the resistance of the potentiometer varies changing the feedback voltage of the position sensor signal circuit. This voltage varies from 0.27-4.65 volts. The MSM monitors this voltage signal to determine the lumbar position.

When a memory set command is received, the MSM records the lumbar 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. The lumbar support is not involved in the easy exit function and the front passenger lumbar vertical support is not involved in memory recall functions.

Refer to Memory Seats Description and Operation.