Power Seats System Description and Operation Folding Seat

The power folding seat system consists of the following components:

The GMLAN serial data is also part of the power folding seat system.

The rear seat module (RSM) must receive GMLAN serial data messages indicating that the following conditions have been met prior to seat operation or when a switch is pressed a chime will sound and the RSM will inhibit operation:

Enabling the RSM using the remote keyless entry transmitter or the driver/passenger door lock switch unlock sequence allows for the system to operate for two minutes before timing out. The RSM will restart the timing procedure each time the recline or stow switch is pressed. After the two minute time period expires, the RSM will discontinue operation until another keyless entry or door unlock sequence takes place. Enabling the RSM by placing the ignition in either the ON or ACCESSORY positions allows for continuous operation of the folding seat system without the time out feature.

The following conditions must also be met before the RSM will allow seat operation:

If seat operation is attempted while the RSM is in the disabled mode an audible chime message will be activated signaling that one of the above conditions has not been met.

To verify that the RSM is calibrated, install a scan tool and observe the Calibrated parameter in the Rear Seat Module data list, the parameter should display Yes. If the RSM is not calibrated refer to Power Folding Seat Calibration .

There are three push button switches that are used to operate the power folding seat; front stow switch, rear stow switch, and recline switch. The front stow switch is located in the right rear quarter trim panel just behind the second row seat. The rear stow and recline switches are located in the right rear trim panel just inside the liftgate. Battery positive voltage is supplied at all times to all three switches from the 3rd ROW SW/RFA Fuse located in the left rear fuse block. The folding seat will operate only in a supervised mode, i.e. press and hold the selected switch button through the entire cycle of operation, or release the switch when the desired seat position is reached. When any folding seat switch is pressed, it sends a 12 volt signal through the switch signal circuit to the RSM. The RSM then commands the appropriate seat motors to move in response to the switch signal.

The rear seat module controls the position of the third row seat. When commanded it moves the seat from the seated position to the stowed position, or, from the stowed position to the seated position. With the seat in the seated position, the RSM can also move the angle of the seat back forward or rearward.

Battery positive voltage is supplied at all times to the module through the battery positive voltage circuit and the RSM Fuse located in the left rear fuse block. This voltage is used to power up the RSM and also to apply power to the seat motors when commanded. The RSM is grounded through the module ground circuit and G401.

The power folding rear seat has three reversible DC motors. These are the seat horizontal motor, the 180 degree rotation motor, and the recline motor. The horizontal motor moves the entire seat forward or rearward, the rotation motor rotates the seat back 180 degrees, and the recline motor moves the seat back forward or rearward. 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.

In order to decrease the stress on each motor, the RSM provides each seat motor with a soft stop that will actually stop the motor before the physical end of travel. Each motor uses a hall effect sensor to determine the position of the seat and the end of travel limits. Module self-calibration is used to determine hard stop limits during the initial power up and every tenth activation thereafter. The soft stop limits are a calibrated count from the determined hard stops.

The seat position sensors are 2 wire hall effect sensors which are an internal part of each motor. The RSM supplies a separate 12 volt reference through the signal circuits to each position sensor, and a common ground through the sensor low reference circuit to each seat position sensor. During seat operation, while the seat motor is active, the position sensor provides the RSM with a single feedback pulse through the signal circuit for every rotation of the motor shaft. The RSM counts the feedback pulses from each sensor to determine the seat position, and the end of travel limits for each of the seat motors.

With the seat in the seated position, and when a stow switch is pressed, battery positive voltage is applied through the switch contacts and the switch signal circuit to the RSM. In response to this signal, the RSM simultaneously applies battery positive voltage through the seat back rotation motor forward control circuit and the seat horizontal motor forward control circuit to the seat motors. The motors are grounded through the respective motor rearward control circuits. The rotation motor runs to rotate the seat back 180 degrees forward and the seat horizontal motor runs to drive the seat cushion forward until it reaches it's hard stop. After seat back rotation and seat horizontal movements are complete, the RSM then applies battery positive voltage through the recline motor rearward control circuit to the recline motor. The motor is grounded through the recline motor forward control circuit. The motor runs to recline the seat back rearward to the stow position. Moving the seat to the seated position works similarly to moving the seat to the stowed position, except battery voltage and ground are applied to the opposite control circuits causing the motors to run in the opposite direction.

There are two limit switches that are involved with seat operation; the load floor position switch and the seat back panel position switch. Battery positive voltage is applied at all times to the switches through their respective supply voltage circuits from the RSM. The following describes how the RSM uses these limit switches during seat operation:

The following describes the sequence of seat movement from the seated position to the stowed position:

The following describes the sequence of seat movement from the stowed position to the seated position:

Power Seats System Description and Operation Front Seat

The driver and passenger power seat systems each consist of the following components:

The seat adjuster and lumbar switches provide both power and ground to the selected seat and lumbar motors. Battery positive voltage is supplied at all times to the driver and passenger seat adjuster switches from the PWR SEATS circuit breaker located in the left rear fuse block. The driver seat adjuster switch is grounded through the switch ground circuit and G200. While the passenger seat adjuster switches are grounded through the switch ground circuit and G201.

All of the seat motors operate independently of each other. 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. There are four seat position motors and one lumbar motor. These are the horizontal motor, front vertical motor, rear vertical motor, seat back recline motor and the lumbar horizontal motor. The seat horizontal motor moves the entire seat forward and rearward. The seat vertical motors may operate independently to tilt the front or rear of the seat cushion up or down. Both motors can also run simultaneously to move the entire seat up or down. The recline motor moves the angle of the seat back forward or rearward and the lumbar horizontal motor moves the lumbar support forward and rearward.

All motors are reversible. For example, when the seat switch is operated to moved the entire seat forward, battery positive voltage is applied through the horizontal forward switch contacts and the seat horizontal forward switch control circuit to the seat horizontal 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 other seat and lumbar motors are also powered this way.