Heated Seats

When the ignition switch is in the RUN position and the driver seat heater switch is set to the LO position, voltage from the HVAC Fuse is fed through circuit 41 to the driver seat heater switch. One set of switch contacts sends an ON signal to the driver seat heater control module through circuit 1462. The second set of switch contacts in the driver seat heater switch sends a signal to the driver seat heater control module through circuit 1501 whether the switch is in the HI (no resistor) or LO (through resistor) position. The third set of contacts determines if the HI or LO indicator is on.

When the driver seat heater control module receives an ON signal from the driver seat heater switch, it closes the normally open set of relay contacts. This sends voltage from the LH HEATED SEAT Fuse through circuit 1440, the relay contacts, circuit 950, the heated seat element in the driver seat cushion cover, circuit 900. the heated seat element in the driver seat back cushion cover, and circuit 750 to G301. This causes both the heated seat elements to heat the seat cushions. The driver seat heater control module monitors the driver seat cushion cover temperature using the heated seat thermistor. It does this by sensing the current flowing through circuit 952, the heated seat thermistor, and circuit 750 to G301.

The driver seat heater control module controls the relay output to maintain a set temperature. It does this by closing the relay until the temperature is exceeded and then turning it off until the seat cools down. For the LO position the relay tries to maintain a temperature of approximately 37.5°C (98.5°F) and for the HI position a temperature of approximately 42.5°C (107.5°F). The system turns off either when the driver seat heater switch is set to the OFF position or the ignition switch has been cycled to the OFF position and then back to the RUN position.

The passenger seat heater, if equipped, works in a similar way.