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Test I: The Driver Heated Seat Is Inoperative

PINPOINT TEST I: THE DRIVER HEATED SEAT IS INOPERATIVE


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Normal Operation
The driver heated seat module receives battery voltage feed on circuit 1048 (LB/WH) and ignition voltage feed on circuit 1040 (RD/BK), and is supplied ground on circuit 676 (PK/OG). When the heated seat control switch is pressed with the ignition switch in RUN or START, a ground signal is sent to the heated seat module on circuit 1020 (DG/VT) to command the system ON or OFF in HI heat mode or circuit 1255 (WH/RD) to command the system ON or OFF in LOW heat mode. When commanded ON, a ground signal is supplied to the heated seat switch from the heated seat module on either circuit 1019 (TN/LB) (HI heat mode) or circuit 1018 (LG/OG) (LOW heat mode) illuminating the switch indicator. The heated seat module also supplies voltage to the cushion and backrest heater mats on circuit 1064 (YE/LB) and ground to the heater mats on circuit 1065 (WH/LB). The cushion and backrest heater mats are connected in series and operate together. Temperature is maintained by the heated seat module using a sensor contained within the cushion heater mat. The heated seat module supplies a reference voltage to the temperature sensor on circuit 1060 (BK/LB) and monitors the return signal from the temperature sensor on circuit 1061 (BN/LB) for adjusting the current flow to the heater mats. The heated seat module is designed to remain ON, heating the seat and maintaining temperature until switched OFF or the time-out period occurs.

Possible Causes
An inoperative driver heated seat can be caused by:
- an open fuse.
- faulty wiring, terminals or connectors.
- a faulty heated seat switch.
- a faulty heater mat.
- a faulty heated seat module.