Electrically Heated Seats - Front Only

The heated seat feature is available only with the memory system. The system's control module, known as the Memory Heated Seat Adjustable Pedal Module (MHSAPM), is located under the driver's seat and controls the front heated seats only. The driver heated seat control switch is located on the driver door trim panel. The switch is hardwired to the Driver Door Module (DDM). When the operator actuates the switch on, the DDM sends a message via the PCI Bus to the MHSAPM requesting heated seat operation. The passenger heated seat control switch is located on the front-passenger door trim panel. The switch is hardwired to the Passenger Door Module (PDM). When the operator actuates the switch on, the PDM sends a message via the PCI Bus to the MHSAPM requesting heated seat operation.

The system offers two seat temperature settings of approximately 96.8 F (36°C) (LO) and approximately 107.6 F (41°C) (HI). As the temperature in the seat rises, the negative temperature coefficient (NTC) resistance decreases and the voltage reading detected by the MHSAPM decreases. The seat heater output is deactivated once the voltage reading reaches its threshold for either setting, high or low. As the temperature decreases, the voltage reading increases until the upper threshold is reached for either setting high or low. At this point the seat heat output is activated once again and this cycle repeats itself as long as the seat heat request is on. The thresholds for low and high settings are preprogrammed into the module memory.

The heated seat switch contain resistors pulled up to 5 volts which are processed by the DDM as the voltage readings indicating desired heat setting high or low.