Cadillac SRX First Generation Forum - 2004 - 2009 Discussion, 3rd row seat compatibility in Cadillac SRX Forums; Trying to find out what issues with adding 3rd row seat to 05' SRX that did not originally have one. ...
Trying to find out what issues with adding 3rd row seat to 05' SRX that did not originally have one. Dealer told me probably compatibility issues with car recognizing the electronics from the added seat. Also mentioned he wasn't sure if mounting holes were there in one without original 3rd row.
I've read the threads about adding one but no actual step by step installation info. or if any compatibility or mounting issues. Also would it matter what year car the 3rd row seat came from? Any help would be appreciated.
Power Seats System Description and Operation (Folding Seat)
The power folding seat system consists of the following components:
• Folding Seat Front Stow Switch
• Folding Seat Rear Stow Switch
• Folding Seat Recline Switch
• Rear Seat Module (RSM)
• Rear Seat Horizontal Motor
• Rear Seat Back Rotation Motor
• Rear Seat Recline Motor
• Rear Seat Horizontal Position Sensor
• Rear Seat Back Rotation Position Sensor
• Rear Seat Recline Position Sensor
• Seat Back Panel Position Switch
• Seat Back Load Floor Position Switch
• 3rd ROW SW/RFA Fuse 30A
• RSM Fuse 30A
The GMLAN serial data is also part of the power folding seat system.
Conditions for Seat Operation and GMLAN Communications
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:
• The gear selector must be in the PARK position.
• The ignition can be in any power mode except CRANKING.
• Either the lift gate or the right rear door must be OPEN.
• The RSM must be enabled by pressing the UNLOCK button on either the remote keyless entry transmitter or the driver/passenger door lock switch three times within 5 seconds, or by placing the ignition in the ON or ACCESSORY position.
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:
• The folding seat back panel must be in the folded position.
• The RSM must be calibrated.
• Both headrests must be removed.
• The battery must have a sufficient charge.
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 .
Rear Seat Switches
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.
Rear Seat Module and Power and Ground
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 load floor switch is located in the back panel of the folding rear seat. When the back panel is placed in the folded position the load floor switch is closed. Battery positive voltage is then applied through the switch contacts and the load floor switch signal circuit to the RSM, and seat operation is allowed. In this position the scan tool Load Floor Switch parameter will display Inactive.
After the power folding rear seat is moved from the seated to the stowed position, the seat back panel is then manually unfolded and deployed over the seat cushion. With the back panel unfolded and deployed over the seat cushion, the load floor switch is now open, the scan tool Load Floor Switch parameter will display Active, and the RSM will not allow seat operation.
• The back panel position switch is located in the lower left corner of the folding rear seat back panel. When the seat back is in either the seated position or in the stowed position the switch is closed, battery positive voltage is applied through the switch contacts and the seat back position switch signal circuit to the RSM indicating that the switch is active. The RSM uses this switch input for the following purposes:
- To determine the soft stop limits of the recline motor when the seat is in the stowed position.
- To determine the soft stop limits for the seat back rotation motor when the back is in the seated position.
- To determine the starting point of the seat back with the seat in the seated position.
- Once the seat back starts to rotate, the seat back position switch contacts open to signal the RSM the initial starting point of the seat back. The RSM then begins to count the sensor pulses in order to set the seat back rotation travel distance.
Seat Operation Sequencing
The following describes the sequence of seat movement from the seated position to the stowed position:
• Start of 180 degree forward rotation of seat back.
• The seat back reclines forward to the upright position.
• Seat cushion moves forward to it's soft stop limit.
• Seat back reclines rearward to the stowed position.
• Manually unfold and deploy the seat back panel over the seat cushion.
The following describes the sequence of seat movement from the stowed position to the seated position:
• Manually retract and fold the seat back panel to the folded position.
• The seat back reclines forward to the upright position.
• The seat back rotates 180 degrees rearward.
• The seat back reclines rearward to it's seated position.
• The seat cushion moves rearward to it's seated position.
The entire rear seat system is pretty much self contained. Looking at the wiring diagrams, the only "external" connections on the Rear Seat Module are the GMLAN bus, power, and ground. All of the information about the safety protocols, and the door lock/unlock and key fob operation are transmitted through the GMLAN. I know of several people who have had this done, so it must not be very complicated.
I have the third row seat, and will never ever use it and I would rather have the stowage compartments in the rear. Any chance your rear compartment interior is in good condtion, Cashmere, and you live within a few hundred miles of Maryland?