Principles of Operation

Seats

Principles of Operation

Power Seat (Driver Only)

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 power seat is hardwired to the seat control switch. The circuits are normally at ground through the seat control switch. An individual motor is switched to voltage and ground when a specific adjustment position is selected.

Heated Seats

A heated seat relay is located underneath each heated seat cushion frame. Voltage is supplied from the Smart Junction Box (SJB) to each heated seat relay coil when the ignition is ON. When a heated seat button is pressed, the HVAC module supplies ground to the driver or passenger heated seat relay coil to energize the relay. This closes the relay contact to supply battery voltage from the SJB to the cushion heater mat. The cushion and backrest heater mats are wired in series and the backrest heater mats are directly connected to ground to complete the electrical circuit to heat a seat.

Each cushion heater mat contains a non-serviceable internal thermostatic switch that closes when cold to complete the heater grid circuit and heat the seat. When hot, the thermostatic switch opens the heater grid circuit and allows the seat to cool. During normal operation, several minutes may be required before seat temperature is increased and several more minutes of cooling before the heater mats continue with heating. The heated seat indicator illuminates continuously while the thermostatic switch cycles open and closed.

The seat should be occupied to correctly test for normal operation. Temperature measuring devices do not provide an accurate method for testing heated seat operation as surface temperatures are subject to human and environmental characteristics. Correct testing requires heater mat resistance measurements which have tight tolerances affecting heat cycle time length.

The heated seat system does not time-out. A heated seat will remain on until the heated seat switch or ignition is switched OFF.