Principles of Operation

PRINCIPLES OF OPERATION

Driver and Passenger Power Seats Without Memory
The driver power seat uses a 6-way power seat track and 3 electric motors directly controlled by a seat mounted 6-way seat control switch for horizontal (forward/rearward), front height and rear height adjustment. The passenger seat uses a 2-way seat track with a single electric motor and is directly controlled by a 2-way seat mounted seat control switch for horizontal adjustment. Both driver and passenger seats can also be equipped with a power recliner mechanism, which uses a single electric motor and is also directly controlled by an 8-way seat control switch (driver seat) or a 4-way seat control switch (passenger).

The driver and passenger power seat and power recliner motors are hard-wired to the seat control switch. The circuits are normally at ground through the seat control switch. An individual motor is switched to power circuit 566 (DG) (driver seat) or circuit 1462 (RD/WH) (passenger seat) and ground circuit 1205 (BK) when a specific adjustment position is selected. The power seat feature operates independent of the position of the ignition switch.

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 outside rear view mirror positions and the power adjustable pedals (if equipped) 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. The driver seat also must be calibrated when a new DSM is installed or after the driver seat track is installed (if repaired or installed new).

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 must be calibrated to the driver seat track for correct memory seat operation. Once the DSM is calibrated to the seat track, it will only allow movement within the calibrated range.

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 additional information concerning MS-CAN bus communication.

Seat Calibration
The DSM is calibrated using a diagnostic tool. The calibration procedure automatically powers the driver power seat through its full range of motion and records the full stop positions by monitoring the motor position sensors. Once the full stop positions or range of the seat have been recorded, the DSM will only operate within the calibrated range. Any input attempting to drive the seat beyond the calibrated range will be ignored. This calibration is used for all seat control functions including manual switch control and memory recall positioning. During the seat calibration, the DSM may identify a function that is inoperative, such as a position sensor not changing. If the DSM identifies a concern that has a related DTC, the DSM will set the related DTC at the end of the validation procedure.

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
- Power outside rear view mirror 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.

Heated Seat System
The driver and passenger heated seat modules (if equipped) share a common battery feed and ground source and have a separate ignition feed. The electronic automatic temperature control (EATC) module includes the heated seat control buttons and indicators. The heated seat system will function when the EATC module is ON or OFF. When a heated seat control button on the EATC module is pressed with the ignition switch in RUN or START, a momentary ground signal is sent to the heated seat module. Upon receiving a signal, the heated seat module will decrease one setting (the sequence is HI, LO, OFF, HI, etc.). When a heated seat is set to HI, both LED indicators above the heated seat control button will illuminate. When a heated seat is set to LO, only the left LED indicator will illuminate. When a heated seat is set to OFF, neither LED will be illuminated.

When the heated seat system is ON, the heated seat module then supplies power to the heating element circuit. The cushion element and backrest element are wired in series and powered by the same output. The heated seat module will remain on for 10 minutes or until the heated seat control button is pressed to cycle the heated seat module to the OFF state. If the ignition source is removed from the module, the heated seat module will enter an OFF state and will not return to ON until the heated seat control button is once again pressed with the ignition switch in RUN. The heated seat module is designed to heat the seat to 37.5°C (99.5°F) in LO setting and 42°C (107.6°F) in HI setting and maintain the temperature until switched off. This temperature is maintained by the heated seat module, located in the seat cushion element, which monitors the temperature sensor and adjusts the current flow to the heating elements.