Principles of Operation
PRINCIPLES OF OPERATIONDriver and Passenger Power Seats Without Memory
The 10-way power seat feature (driver seat only) moves the seat in 10 possible directions: the seat can be moved forward or backward and the front and back of the cushion can be moved up and down independently. The backrest of the seat can be moved forward and backward, and the lumbar in and out. All 10 positions are controlled by one switch. The power seat feature operates independent of the position of the ignition.
The 6-way power seat feature moves the seat in 6 possible directions: the seat can be moved forward or backward and the front and back of the cushion can be moved up and down independently. The power seat feature operates independent of the position of the ignition.
The power seat motors are hardwired to the seat control switch. The circuits are normally at ground through the seat control switch. An individual circuit is switched to power when a specific adjustment position is selected.
Power Driver Seat With Memory
The memory driver seat feature allows the driver to program a personalized seat position that can be recalled using the memory switch or a remote keyless entry (RKE) transmitter. There are 2 memory settings possible. The power adjustable pedals are also stored and recalled with the power driver seat positions.
The driver power seat is controlled by the driver seat module (DSM), if equipped. A new DSM must be configured after installation. Refer to Information Bus (Module Communications Network).
The driver seat control switch provides voltage to the DSM when activated. The NEUTRAL position of each driver seat control switch position is a ground state through the seat control switch contacts. A voltage input causes the DSM to power the appropriate motor until the input is removed. Ground is the normal state of the motor circuits through the DSM and is not switched to control the motors. The DSM internally switches the appropriate circuit from ground to power for operating the motors.
As the seat is adjusted, the DSM constantly monitors the motor position sensors to record the current seat position. The DSM will remove power from the motor upon termination of the seat control switch input or if the DSM does not see movement from the motor by monitoring the position sensor.
The DSM communicates diagnostic trouble code (DTC) and other information using the MS-CAN communication bus. It should be noted for diagnostics that because CAN bus communication is more robust and reliable than other methods, it may be possible to have limited module communication with one of the CAN bus circuits disconnected or shorted to ground. Refer to Information Bus (Module Communications Network) for information concerning MS-CAN bus communication.
Programming Memory Seat Positions
A power driver seat position can be stored at any time. The driver must move the seat to the desired position using the driver seat control switch. The driver must then depress the memory SET switch which activates the memory SET switch light emitting diode (LED). Within 5 seconds (before the LED goes out), the driver must select a memory position. Memory 1 is selected by depressing memory switch 1 Memory 2 is selected by depressing memory switch 2.
If no memory switch input is received within the 5-second time limit, the operation is aborted and the memory SET switch LED is turned off. If one of the following inputs is received during the 5-second programming limit, the operation is aborted and the memory SET switch LED is turned off:
- Power driver seat control switch
- Memory SET switch
- Power adjustable pedal switch
Recalling a Stored Memory Seat Position
NOTE: A memory recall can be initiated only if the vehicle is in PARK or NEUTRAL gear and the ignition switch is not in START. A memory recall in progress will not be affected by moving the ignition switch to START or by moving the gearshift lever out of PARK or NEUTRAL.
Once the driver has stored the driver seat position, the driver can recall the setting by depressing the corresponding memory switch or by using a programmed remote entry transmitter.
The driver can recall the desired driver seat position by depressing one of the memory recall switches. Depressing memory switch 1 will initiate a recall of the power driver seat position stored in Memory 1 Depressing memory switch 2 will initiate a recall of the power driver seat position stored in Memory 2.
A remote entry transmitter can be used to recall previously set memory positions. The transmitter that has been assigned with personality 1 is capable of recalling memory position 1 only. Similarly, the personality 2 transmitter can recall only memory position 2.
Memory recall occurs when the unlock switch is depressed on the remote entry transmitter. The second depression of the unlock switch, which unlocks passenger doors, does not initiate a memory recall.
A memory recall in progress does not prohibit the initiation of another memory recall; the most recently requested memory recall will be executed.
Memory positions that have not been programmed will not initiate any motion for the power driver seat, power memory rear view mirrors or adjustable pedals.
Easy Exit/Easy Entry
The easy exit function moves the seat backwards about 2 inches when the ignition key is removed from the ignition switch. The DSM receives a key out command over the MS-CAN communication network and powers the driver seat rearward. This function will not operate if the function has been deactivated. The DSM will also cancel this operation if a valid input command is received, such as the seat control switch or memory recall request.
The DSM will record the current seat position before powering the seat for an easy exit function. This recorded position will be used to return the seat to this position on the easy entry operation. During easy entry operation, the seat is returned to the position previous to the easy exit operation. Easy entry operation will be cancelled if a valid input command is received by the DSM.
The easy exit/easy entry feature can be activated or deactivated using a scan tool or via the message center. Refer to Information Bus (Module Communications Network) or the owner's literature.
Heated Seats
The driver and passenger heated seats share a common ignition and battery feed to the heated seat control switch assembly. The ignition feed powers the logic board and illumination of the heated seat switch assembly and the battery feed is used to provide voltage to the heater mats. The heated seat switch assembly uses a shared ground for the logic board and illumination.
When a heated seat switch is pressed with the ignition switch in RUN or START, a momentary ground is provided to the logic board of the heated seat switch assembly. The logic board then activates an internal relay in the heated seat switch assembly that provides voltage to a bi-metallic thermostat that is part of the seat cushion heater mat.
The driver seat cushion and backrest heater mats are wired in series as are the passenger seat cushion and backrest heater mats. The heated seat system is designed to maintain the temperature by the opening (no voltage to the heated seat mats) and closing (voltage supplied to the heated seat mats) of the bi-metallic thermostat.
The heated seat will remain ON until the heated seat switch is pressed or until ignition voltage is removed from the heated seat switch assembly.
Third Row Power-Fold Seat
CAUTION:
- To prevent possible damage to the third row seat or the safety belts, make sure that the safety belts are not fastened when moving the seat to the load floor position.
- Make sure that no objects such as books, purses or briefcases are on the floor in front of the third row seats or on the seat cushion before lowering the backrest(s).
For the third row power-fold seat to operate, a shared ground is supplied by the smart junction box (SJB) to both of the power-fold seat relays, enabling the seats to then be moved by pressing one of the third row power-fold seat switches. The third row power-fold seat operates only when the vehicle is in PARK and the liftgate glass or liftgate door are open.
The power fold seat relays will be provided ground on the coil side from the SJB for 30 minutes when the transmission selector is in P, and the liftgate, or liftgate glass is open. The ground will be disabled 30 minutes after turning the vehicle OFF. If the ground is disabled after 30 minutes, the ground can be enabled by opening any door, pressing the unlock key on the key fob, pressing any keyless keypad button or turning the ignition key.
The third row power-fold seat motors transfer movement to a drive screw and bracket assembly to raise and lower the seat backrest and cushion.