Ford Escape: Front Seats / Description and Operation - Front Seats - System Operation and Component Description

System Operation

System Diagram - Memory Seat

Network Message Chart - Memory Seat

  DSM Network Input Messages

Memory Seat Operation

The driver seat control switch provides a voltage signal to the DSM only when activated. This voltage signal causes the DSM to power the appropriate motor until the input is removed. The motor circuits are normally grounded through the DSM . The DSM internally switches the appropriate circuit from ground to voltage to operate the motors.

As the seat is adjusted, the DSM monitors the motor position sensors to record the current seat position. The DSM removes voltage from the motor upon termination of the seat control switch input or if the DSM does not detect movement from the motor while monitoring the position sensor during a memory recall operation.

If the DSM loses the signal from any of the motor position sensors, the affected seat motor operates in jog mode. Jog mode allows limited operation of the affected seat motor using only the seat control switch. When the seat control switch is operated in jog mode, the seat moves in the desired direction for one second, then stops. The seat control switch must be released, then pressed again in order to move the seat for an additional second. Jog mode is an indication that there is a seat motor sensor fault. If the memory seat is operating in jog mode, a DTC sets in the DSM .

DSM Hard Stop/Soft Stop

A hard stop occurs when one of the memory seat track or backrest axes physically reach the end of travel and can go no further. A soft stop occurs when the seat stops before it physically reaches the end of travel. The hard stop is set by seat design and cannot be changed or adjusted. The soft stop is set by the DSM . The seat track axes are forward/rearward, front up/down and rear up/down. The backrest axis is recline forward/backward. To prevent unnecessary stress on the seat and motors, the DSM sets soft stop positions, 2 for each moving axis. The DSM uses a preset distance from the hard stop to determine where the soft stop occurs. When an axis reaches the hard stop and the switch is held for approximately one second, the DSM briefly reverses direction and establishes 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.

Easy Entry/Exit

The easy entry/exit feature is a function of the DSM that moves the driver seat back approximately 50.8 mm (2 in) (unless seat is already positioned at or near the end of travel) when the ignition is turned off. The DSM receives ignition off status over the MS-CAN and operates the driver seat rearward. The DSM cancels this operation if a valid input command is received from the driver seat control switch, memory set switch, exterior mirror control switch or if the function has been disabled.

The DSM records the current seat positions before operating the seat for an easy exit operation. During easy entry operation (when the ignition is turned on), the seat is returned to the recorded seat position prior to the easy exit operation. Easy entry operation is cancelled if a valid input command is received by the DSM . A memory position recall using the memory set switch also overrides the easy exit operation.

The easy entry/exit feature can be enabled/disabled on the message center. For information on programming vehicle settings in the message center, refer to the Owner's Literature.

Power Seat Operation - Passenger and Driver (Without Memory)

The seat control switches contain normally closed contacts which are grounded. An individual circuit is switched to voltage when a specific adjustment position is selected. The seat control switches are hard-wired directly to the applicable seat motors. The motor direction is determined by the polarity of voltage supplied from the seat control switch.

Heated Seat Operation

The driver and passenger heated seat control buttons and indicators are located on the HVAC module. The heated seat system functions independently of the vehicle's climate control system. Each time the heated seat button is pressed, the system decreases one setting (the sequence is high, med, low, off, high, etc.).

When activated, the HVAC module supplies voltage to the selected seat heater circuit. Each seat cushion heater mat and backrest heater mat is connected in a series circuit to the HVAC module and powered by the output circuit for that seat. The HVAC module monitors inputs from a temperature sensor located in each seat cushion heater mat, and maintains seat temperature by cycling the heater circuits on/off. The heated seat remains on until the heated seat switch button is pressed to cycle the HVAC module off or the ignition is OFF.

If a fault is detected by the HVAC module, the module stops supplying voltage to that individual left or right seat the fault was detected on until the ignition is cycled off and then on.

Remote Start Climate Operation

Different climate control modes/preferences can be selected when the vehicle is started using the remote start feature. This can be accessed through the message center. For additional information on how to set the remote start preferences, refer to the Owner's Literature. When the driver seat and/or passenger seat is set to AUTO mode, the driver/passenger heated seat activates in full heat mode when the outside temperature is less than 0° C (32° F) any time the vehicle is started using the remote start feature. No heated seat adjustments are recognized during remote start operation.

Component Description

Seat Control Switch - Without Memory

The seat control switch contains normally closed contacts which are grounded. When a specific adjustment position is selected, an individual circuit is switched to voltage.

Seat Control Switch - With Memory

The driver seat control switch is hard-wired to the DSM , which controls seat operation. When a specific seat adjustment position is selected, an individual circuit is switched to voltage.

DSM

The driver seat control switch and power memory seat motors are hard-wired to the DSM . The DSM controls the operation of the power memory seat. The DSM communicates on the MS-CAN . PMI is required on the DSM when a new DSM is installed. The DSM hard stop/soft stops must be set/reset any time a new DSM , driver front seat horizontal motor, driver front seat track or driver front seat backrest is installed.

Memory Set Switch

The memory set switch (part of the driver door lock switch assembly) contains 3 momentary contact switches. It is hard-wired to the DDM and is used to recall 1 of 3 memory positions stored in the DSM .

Driver Front Seat Track - Without Memory

There are 3 front seat track bi-directional motors present on power front seat tracks. The horizontal (fore/aft) front seat track motor is the only seat track motor which can be serviced separately from the seat track assembly. All other seat track motors (front height, rear height) are serviced as part of the seat track assembly. The front seat track motors move the power seat forward/backward and up/down depending on the polarity of voltage supplied from the seat control switch.

Driver Front Seat Track - With Memory

There are 3 front seat track bi-directional motors present on power front seat tracks. The horizontal (fore/aft) front seat track motor is the only seat track motor which can be serviced separately from the seat track assembly. All other seat track motors (front height, rear height) are serviced as part of the seat track assembly. The front seat track motors move the power seat forward/backward and up/down depending on the polarity of voltage supplied from the DSM . Each seat track motor contains a Hall-effect sensor which provides seat track position information to the DSM for setting/obtaining desired preset seat memory positions.

Passenger Front Seat Track

The passenger power seat is equipped with 2 front seat track bi-directional motors. The horizontal (fore/aft) front seat track motor is the only seat track motor which can be serviced separately from the seat track assembly. The front seat height motor is serviced with the front seat track. The front seat track motors move the power seat forward/backward and up/down depending on the polarity of voltage supplied from the seat control switch.

Driver Front Seat Backrest

If equipped with power recline, the driver seat backrest contains a bi-directional motor which is integral to the seat backrest frame assembly. If the vehicle is equipped with the memory feature, the seat backrest motor contains a Hall-effect sensor which provides seat backrest position information to the DSM for setting/obtaining desired preset seat memory positions. The seat backrest motor moves the seat backrest forward/backward depending on the polarity of voltage supplied from the DSM (if equipped with memory) or from the seat control switch.

Passenger Front Seat Backrest

If equipped with power recline, the passenger front seat backrest contains a bi-directional motor which is integral to the front seat backrest. The front seat backrest motor moves the front seat backrest forward/backward depending on the polarity of voltage supplied from the seat control switch.

HVAC Module

The HVAC module contains the heated seat or heated/ventilated seat control buttons. If equipped with heated seats, the HVAC module monitors the seat cushion temperature sensor and supplies heater current to the seat cushion and backrest heater mats until the desired setpoint temperature is reached. Once the setpoint temperature is reached, the HVAC module cycles the heater circuits on/off as required to maintain the setpoint temperature.

Heater Mat

If equipped with heated seats, the cushion heater mats are each equipped with a temperature sensor (thermistor) which provides feedback to the HVAC module. The cushion and backrest heater mats are connected in series.

Front Seat Power Lumbar Assembly

The front seat power lumbar assembly is mounted to the backrest (serviced as an assembly).