Test A: The Heated Seat Is Inoperative

PINPOINT TESTS

A1:

A1-A3:

A3-A5:

A5 Continued:

Normal Operation
The driver and passenger heated seat switches share common ignition voltage feed to circuit 15-HC1 (GN/BU) spliced to the driver heated seat switch circuit 15-HC6 (GN/YE) and the passenger heated seat switch circuit 15-HC9 (GN/BK). The heated seat switches share spliced ground to circuits 31-LH29 (BK) (driver) and 31-LH43 (BK) (passenger). The heated seat switches are a latching style switch with an LED ON/OFF indicator. Continuity through the switch will remain whether voltage is supplied to it or not until switched OFF. With the ignition switch in RUN or START and a heated seat switch in the ON position, voltage is applied to circuit 15S-HC6 (GN/YE) (driver) or 15S-HC9 (GN/BK) (passenger) and connected to a 2-lead bi-metallic switch type thermostat incorporated into each cushions heated seat element. Each thermostat is connected by a series circuit to the cushion heated seat element internally. Each seats cushion and backrest heated seat elements are also connected by a series circuit to ground circuit 31-HC8 (BK) (driver) or 31-HC11 (BK) (passenger). With a heated seat switch ON, the cushion thermostat will cycle OPEN or CLOSED to allow current flow to the heated seat elements and regulate the seat cushion temperature at approximately 40°C (104°F). If a heated seat is ON and the ignition source voltage is removed, the heated seat will enter an OFF state but will return ON when the ignition voltage is restored. The temperature sensor is not a serviceable item and must be installed as part of a new cushion heated seat element.

Possible Causes
An inoperative heated seat can be caused by:
- an open fuse.
- circuit 15-HC1 (GN/BU) open.
- circuit 15-HC6 (GN/YE) open.
- circuit 15-HC9 (GN/BK) open.
- circuit 15S-HC6 (GN/YE) open.
- circuit 15S-HC9 (GN/BK) open.
- circuit 31-LH29 (BK) open.
- circuit 31-LH43 (BK) open.
- circuit 31-HC8 (BK) open.
- circuit 31-HC11 (BK) open.
- a faulty heated seat switch.
- a faulty heated seat element.
- a faulty heated seat temperature sensor.