Lincoln Corsair: Rear Seats / Description and Operation - Rear Seats - System Operation and Component Description

System Operation

Power Fold Down Backrest

For power fold seat operation, system voltage is provided at all times to LH and RH rear seat backrest release relays (integral to the BJB and not serviceable separately). 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 power fold seat control switch is pressed, it supplies the ground to activate the LH or RH rear seat backrest release relay. When the relay is activated, it supplies power to the power fold seat motor to retract the cable (connected to the same seat mechanism as the manual release pull strap) that releases the backrest recliner latches, allowing the backrest assist spring to fold the backrest forward. 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 backrest must be manually latched upright.

Rear Heated Seats

The heated seats are controlled by the heated rear seat module located under the LH rear seat cushion frame. When the LH or RH heated seat switch is pressed, a momentary ground signal is sent to the heated rear seat module to activate the heated seat feature. When the heated seat feature is active, the heated rear seat module supplies voltage to the heater circuit. The seat cushion and backrest heater mats are wired in series. The heated rear seat module monitors input from a temperature sensor located in each backrest heater mat and maintains seat temperature by cycling output voltage to the heater grids as necessary to maintain the setpoint temperature. The heated rear seat module supplies voltage to illuminate the appropriate indicator circuit(s) in the heated seat switch when the system is active. In high mode, both indicators on the heated seat switch illuminate. In low mode, only the low indicator illuminates. The heated rear seat module does not time out and remains on until switched off or ignition is off.

The heated rear 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, reset the heated rear seat module by cycling the ignition OFF and then ON. After the heated rear seat module has been reset, the module returns to an off state.

Component Description

Power Fold Seat Control Switch

The power fold seat control switch is a momentary contact switch that, when pressed, supplies a ground input to the LH or RH rear seat backrest release relay.

Power Fold Seat Motor

The 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 motor.

Heated Seat Switch

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

Heated Rear Seat Module

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

Seat Heater Mat

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