Principles of Operation
Seats
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) or a 4-way seat control switch (passenger).
The power seat and power recliner motors are hard-wired to the seat control switch. An individual motor is switched to voltage and ground when a specific adjustment position is selected.
Driver Power Seat With Memory
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.
NOTE: Verify good battery condition before diagnosing the memory seat system. Poor battery condition may interfere with memory seat operation, even if vehicle starting is possible.
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 power adjustable pedals position are also stored and recalled with the power driver seat positions. For information on programming memory positions or recalling a stored memory position, refer to Memory Position Programming Programming and Relearning.
The driver power seat is controlled by the Driver Seat Module (DSM), if equipped. The Driver Seat Module (DSM) is located underneath the driver seat cushion frame. PMI must be carried out when installing a new DSM. Refer to Information Bus. The DSM does not require calibration to the driver seat track.
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 has the ability for soft stops both at the upper and lower limits on all axis of the driver seat. When an axis reaches the hard stop and the switch is held for approximately one second it will then back up 180 msec and establish the soft stop for that axis in that direction. The DSM uses this 'back up' strategy to check sensor integrity any time movement has stopped prematurely due to a sensor failure or obstruction.
The DSM communicates DTC and other information using the Medium Speed Controller Area Network (MS-CAN) communication bus. It should be noted for diagnostics that because Controller Area Network (CAN)) bus communication is more robust and reliable than other methods, it may be possible to have limited module communication with one of the CACAN bus circuits disconnected or shorted to ground. Refer to Information Bus for additional information concerning MS-CAN bus communication.
This only diagnoses concerns specific to the memory seat. To diagnose a memory power mirror concern, refer to Mirrors.
Remote Keyless Entry (RKE) Transmitter
A RKE transmitter can be used to recall previously set memory positions but must first be associated to that memory position. The transmitter associated with personality 1 is capable of recalling memory position 1 only. Similarly, the associated personality 2 transmitter can recall only memory position 2. Up to 8 RKE transmitters can be associated for memory position recall.
Memory recall occurs when the unlock switch is depressed on the RKE transmitter if it has been associated with a memory position. 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.
To associate a remote transmitter to a memory position, refer to Remote Keyless Entry Transmitter Programming in Locks. To diagnose a RKE transmitter concern, refer to Locks. Transmitter
Easy Entry/Exit Feature
The easy entry/exit feature 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 seat is less than the travel distance to the end of the track or the function has been disabled. 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 operation. 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 entry/exit feature can be disabled and enabled by selecting easy entry on the message center display with the setup control button and pressing the reset control to select on or off from the display menu. Refer to driver controls in the Owner's Literature for additional instructions for using the message center.
Heated Seats - Front
NOTICE: Do not install a new heater mat on a front passenger seat cushion. If a new cushion heater mat is needed on the front passenger seat, an Occupant Classification Sensor (OCS) service kit equipped with a heater mat must be installed. Failure to follow this instruction may result in incorrect operation of the OCS system.
The heated seat module receives separate battery and ignition feeds and a ground source. The HVAC module includes the heated seat control buttons and indicators. The heated seat system will function when the HVAC module is on or off. When a heated seat control button on the HVAC 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 high, low, off, high, etc.). When a heated seat is set to high, both LED indicators above the heated seat control button will illuminate. When a heated seat is set to low, only the left LED indicator will illuminate. When a heated seat is set to off, neither LED will be illuminated. Refer to Heating and Air Conditioning.
When the heated seat system is on, the heated seat module then supplies voltage to the heater mat circuit. The cushion and backrest heater mats are wired in series and supplied voltage by the same output. The heated seat module will remain on 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 heated seat 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 37.3°C (99.1°F) in low setting and 62.4°C (144.3°F) in high setting and maintain the temperature until switched off. This temperature is maintained by the heated seat module, located under the passenger seat, which monitors the temperature sensor and adjusts the current flow to the heater mats.
Heated Seats - Rear (Taurus X)
Vehicles equipped with rear heated seats are equipped with a single-heated seat module to control both rear heated seats. The heated seat module is located under the front console. When the heated seat switch is pressed with the ignition switch in RUN, a momentary ground signal is sent to the heated seat module. The heated seat module then supplies voltage to the heater circuit. The seat cushion and backrest heater mats are wired in series and supplied voltage by the same output. The heated seat module monitors inputs from a temperature sensor, located in each seat's cushion heater mat and maintains seat temperature by cycling the heater feed output as necessary to maintain the setpoint temperature. The heated seat module also will send voltage to the separate indicator circuit at the heated seat switch to indicate an on state. The heated seat module will remain on until the heated seat switch is pressed for that circuit that is currently on and receives a second momentary ground signal or the ignition switch is set to OFF.
If a fault is detected by the heated seat module, the module will stop supplying voltage to that individual left or right seat as well as the switch indicator on which that fault was detected. The faults detected will be: a heater feed circuit short to battery, ground or open; sensor circuit short to battery or open; heated seat switch stuck closed to ground or heated seat switch low and high inputs shorted together. To reset the module, cycle the ignition switch OFF and then ON. After the heated seat module has been reset, the module will return to an off state. The heated seat module does not report DTCs and does not communicate on any communication network.
Second Row Power-Fold Seat (Taurus X)
NOTE: The Smart Junction Box (SJB) may also be identified as GEM.
For the second row power-fold seat to operate, voltage is supplied by the SJB to the power-fold seat relay, enabling the seats to then be moved by pressing the second row power-fold seat switch.
The power-fold seat relay will be provided voltage on the coil side from the SJB for 30 minutes when the transmission selector is in PARK, and the liftgate, or liftgate glass, is open. The voltage will be disabled 30 minutes after turning the vehicle OFF. If the relay is disabled after 30 minutes, it 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 second row power-fold seat motor retracts a cable to release the backrest recliner latches and allows the backrest assist spring to fold the backrest forward onto the seat cushion. The power-fold seat motor continues to retract to release the seat-to floor latches and allows the spring assist strut to lift and tumble the seat forward to the E-Z entry position for 3rd row seat access. Immediately after the seat is fully released, the power-fold seat motor returns the release cable and latches to a relaxed state, ready for manual latching. To return to a seating position, the seat must be manually latched to the floor and the backrest must be manually latched upright.
Second Row 60/40 Percent E-Z Entry Seats (Taurus X)
NOTICE: The backrest must be folded flat (fully downward) before the floor latches can be released. Make sure there are no objects on the seat before lowering the backrest(s). Failure to follow this instruction may cause damage or incorrect operation of the seat.
The 60/40 E-Z entry seats have the following 3 functional positions:
- Backrest fold-flat
- E-Z entry (fold-forward position for third row access)
- Upright
For backrest fold-flat position, lower the head restraint, pull the release strap or recliner handle up and fold the backrest fully downward. To return upright (seating position), pivot and raise the backrest toward the rear of the vehicle until locked upright (vertical) for occupancy.
For E-Z entry, move the backrest to the fold-flat position and pull the release strap or recliner handle a second time to release the floor latches. Turn the recliner handle or pull the third row occupant release strap a second time until the seat releases from the latch strikers. Lift up on the rear of the seat, pivoting it forward, away from the third row seats and up to the E-Z entry position. To return the seat, push the rear of the seat down with moderate force to latch the seat to the strikers. Make sure the seat is latched to the strikers by lifting up on the rear of the seat. Lift and pivot the top of the backrest toward the rear of the vehicle, rotating the backrest until you hear a click, locking it in the upright (vertical) position. Make sure the seat backrest is locked in position.
For access to the third row seats through the rear doors, fold the seat up out of the way (E-Z entry position), after the backrest has been folded down. To release the latch feet from the strikers and position the seat to the E-Z entry position, the backrest must be folded forward and all the way down. Remove anything between the backrest and cushion that may prevent the backrest from folding all the way down.