Pacifica V6-3.8L VIN L (2005)
Seat Heater: Description and Operation
Heated Seat Elements
Heated Seat Element - Typical
The heated seat system utilizes two heated seat elements in each seat, one for the seat cushion and the other for the seat back. Although two different
heated seat systems are used for the front and 2nd row rear seats, the heated seat elements function the same way. The two elements for each 2nd row
rear seat are connected in series with the 2nd row Heated Seat Module (HSM). The two elements for each front seat are connected in parallel with the
Memory Heated Seat Adjustable Pedal Module (MHSAPM). One temperature sensor is used for each rear seat only, and it is located in the rear seat
cushion heated seat element. The front heated seat system does not utilize a temperature sensor the heated seat elements. The heated seat temperature
sensor is a Negative Temperature Coefficient (NTC) thermistor.
The heated seat elements are glued onto the seat cushion and seat back cushion foam. The heated seat elements and the temperature sensor cannot be
adjusted or repaired and, if faulty or damaged, the heated seat element assembly must be replaced. Refer to the procedure later.
The heated seat elements resist the flow of electrical current. When battery current is passed through the elements, the energy lost by the resistance of the
elements is released in the form of heat.
The rear heated seat temperature sensor is a Negative Temperature Coefficient (NTC) thermistor. When the temperature of the rear seat cushion cover
rises, the resistance of the sensor decreases. The rear heated seat module supplies five-volts to one side of each sensor, and monitors the voltage drop
through the sensor on a dedicated hardwired return circuit. The module uses this temperature sensor input to monitor the temperature of the seat cushion,
and regulates the 12v current flow to the heated seat elements accordingly.