Lincoln Nautilus: Rear Seats / Rear Seats - System Operation and Component Description. Description and Operation

System Operation

Rear Heated Seats

The heated seats operate in a sequence of high, low and off with each press of the heated seat switch. Rear heated seats are equipped with a single heated seat module to control both outboard rear heated seats. The heated seat module is attached to the underside of the rear seat cushion. The heated seat switch buttons are located in the rear panel of the front floor console. When the heated seat switch is pressed, a momentary ground signal is sent to the heated seat module. The heated seat module then supplies voltage to the appropriate seat heater mat circuit. The seat cushion and backrest heater mats are wired in series and supplied voltage by the same module 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 sends voltage to the separate indicator circuit at the heated seat switch to indicate an on state. The heated seat module remains on until switched off or the ignition is set to OFF. The heated seat function does not time out.

The heated seat module does not report Diagnostic Trouble Codes (DTCs) and does not communicate on any network. If a fault is detected, the affected seat system is disabled. The faults detected are:

• a heater feed circuit short to battery, ground or open.
• sensor circuit short to battery or open.
• heated seat switch stuck closed to ground.

After the fault is corrected, the heated seat module needs to be reset by cycling the ignition OFF and then ON. After the heated seat module has been reset, the module returns to an off state.

Power-Fold Down Backrest

For second row power-fold seat operation, system voltage is provided at all times to LH and RH second row release relays by the BJB . Voltage is provided to the coil side of the relays from the BCM for 10 minutes after ignition is turned off when the transmission selector is in PARK, and the liftgate door is open. After 10 minutes, the system can be enabled by opening any door, pressing the unlock key on the key fob, pressing any keyless keypad button or turning the ignition ON.

When the second row seat control switch is pressed, it supplies the ground to activate the LH or RH second row release relay. When the relay is activated, voltage is provided to the second row power-fold seat motor to release the backrest.

Component Description

Power-Fold Seat Control Switch

The power-fold seat switch is a momentary contact switch that, when pressed, completes a circuit to chassis ground on the control circuits of the LH or RH second row release relays which provide voltage to the power-fold seat motors.

Second Row Power-Fold Seat Motors

The second row power-fold seat motors release a locking mechanism allowing the seat backrest to fold down onto the seat cushion. When the LH or RH power-fold seat control switch is activated, voltage is applied to operate the associated second row power-fold seat motor.

Heated Seat Switch

The heated seat switch is a momentary contact switch that, when pressed, completes a circuit to chassis ground.

Heated Seat Module

When commanded by the heated seat switch, the heated seat module monitors the appropriate seat cushion temperature sensor(s) 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 heated seat module cycles the heater circuits on/off as required to maintain the setpoint temperature. The heated seat module does not report Diagnostic Trouble Codes (DTCs) and does not communicate on any network. If the heated seat module detects a fault, the affected seat system is disabled.

Seat Heater Mat

Each seat cushion heater mat is equipped with a temperature sensor (thermistor) which provides feedback to the heated seat module. The cushion and backrest heater mats are connected in series.